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Article

Continuous Fabrication Process of Aluminum Foam from Foaming to Press Forming

by
Yoshihiko Hangai
*,
Yuito Kaneko
and
Kenji Amagai
Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Japan
*
Author to whom correspondence should be addressed.
Metals 2025, 15(6), 633; https://doi.org/10.3390/met15060633
Submission received: 29 April 2025 / Revised: 29 May 2025 / Accepted: 3 June 2025 / Published: 4 June 2025
Browse Figures
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Abstract

Aluminum foam is expected to be a leading candidate for lightweight parts due to its light weight and excellent shock-absorption and sound-absorption properties. In order to use it as a part, it is essential to form it into the desired shape. However, the cell walls that form the pores are composed of thin aluminum. When aluminum foam is formed, the cell walls easily fracture and the pores collapse. This results in the loss of the properties of the aluminum foam. Past studies have shown that press forming aluminum foam immediately after foaming, while it is still in the softened state, prevents cell wall failure and pore deformation. In this study, we attempted to perform a continuous process from the foaming of the precursor to the press forming of aluminum foam for three precursors, for the purpose of the continuous production of aluminum foam with desired shapes. It was shown that it is possible to continuously and sequentially foam the precursors by heating and press forming the foamed samples. In addition, aluminum foam with a similar shape, porosity, and pore structure can be fabricated using the continuous process. Also, it was shown that aluminum foam with complex shapes can also be continuously fabricated by using a complex-shaped die. Furthermore, it was indicated that the use of a die in press forming can shorten the cooling time and reduce the production time.

1. Introduction

Aluminum foam contains many pores inside the aluminum, and is used as a component of transportation equipment and building materials because of its light weight, and shock-absorption, sound-absorption, and heat-insulation properties [1,2,3,4,5,6]. To be used as a part, it is essential to form it into the desired shape. However, the cell walls that form the pores are composed of thin aluminum, and when aluminum foam is formed, the cell walls easily fracture and the pores collapse, resulting in the loss of the properties of aluminum foam. Previous studies of forming aluminum foam have attempted laser processing at room temperature [7,8,9,10,11], incremental forming [12,13,14], compression forming [15,16,17,18,19], extrusion and rolling [20,21,22], bulge forming [23,24], and compression forming in a solid–liquid coexisting state after heating from room temperature [25,26]. However, the deformation rate, at which forming can be performed, was low, and it has not been possible to achieve a large deformation as in press forming or roll forming. Therefore, in the precursor foaming method [27,28,29], the precursor was conventionally placed in a mold during foaming and the entire mold was heated [30,31,32]. Although foaming in a mold was a simple method, it required a mold disassembly process after foaming and the mold was also heated, making it difficult to control the temperature of the foamed aluminum.
To solve this problem, the authors showed that the forming of aluminum foam in the softened state immediately after foaming prevents cell wall failure and pore deformation [33,34,35]. Press forming is generally a high-productivity, mass-production process that is widely used in the manufacturing of parts. When the precursor is heated above the solidus temperature, the gas generated by the decomposition of the foaming agent causes the aluminum to expand, and when it exceeds the liquidus temperature, it foams significantly [36,37]. It has been found that after foaming and the cessation of heating, but before the temperature decreases below the liquidus temperature, the aluminum foam that is foamed into a spherical shape can be formed into a flat shape while maintaining its pores by press forming. The in-situ observation of pore deformation and material flow by X-ray transmission during press forming showed that the pores of the aluminum foam were collapsed and the aluminum foam became denser when the precursor was cooled and press formed at room temperature. In contrast, it was shown that when the aluminum foam was pressed immediately after foaming but before the temperature went below the liquidus temperature, the pores were not collapsed, but were moved by the material flow while maintaining its pores [33]. Furthermore, compression tests of the aluminum foam samples indicated that the aluminum foam that was press formed immediately after foaming exhibited similar compressive properties to that of the aluminum foam that had not been press formed [35]. From these results, it is expected that it will be possible to mass-produce aluminum foam of desired shapes by continuously foaming a large number of precursors and sequentially press forming them immediately after foaming using a belt conveyor [31] in the future.
In this study, we attempted to perform a series of processes continuously from the foaming of the precursor to the press forming of the three precursors. First, we attempted to fabricate aluminum foam with a flat shape, then measured the porosity and thickness of the obtained samples as well as observed the pore structure by X-ray computed tomography (CT) to evaluate whether a similar aluminum foam could be obtained in all three samples. Next, based on these results, we also attempted the foaming and continuous press forming of foamed aluminum samples into wave shapes. From these experiments, we examined the feasibility of the continuous production of aluminum foam using press forming.

2. Materials and Methods

2.1. Precursor Fabrication Method

Precursors used in this study were fabricated by a friction stir welding (FSW) method [38,39,40,41,42,43,44,45,46]. First, titanium hydride powder (TiH2, particle size less than 45 μm, Kojundo Chemical Laboratory Co., Ltd., Sakado, Japan) as a foaming agent and alumina powder (Al2O3, particle size about 1 μm, Kojundo Chemical Laboratory Co., Ltd., Sakado, Japan) as a pore structure stabilizer were mixed. Then, as is shown in Figure 1a, two Al-Si-Cu aluminum alloy JIS (Japan Industrial Standards) H5302 ADC12 die-casting plates were laminated by placing the powder mixture between them. Table 1 shows the chemical requirements of JIS ADC12 [47]. A pore structure stabilizer increases the thickening effect of molten aluminum during precursor foaming and prevents the pores from floating and coalescing into coarse pores. Next, as is shown in Figure 1b, the FSW tool was traversed over the area of the laminate where the powder mixture was placed, and the powder was mixed into the ADC12 plates. The FSW tool has a shoulder diameter of 17 mm, a probe length of 4.8 mm, and an M6 threaded probe made of tool steel. Since only a small precursor can be obtained with a one-pass tool traversal, a multi-pass method [48,49,50,51,52] was used to obtain a larger precursor. After the first tool traversal, the tool was shifted by 5 mm, perpendicular to the tool traversal direction, and the tool was traversed again. This was repeated for a total of four lines. In addition, in order to sufficiently mix the powder into the ADC12 plates, the same areas that were traversed in four lines were stirred a total of four times by repeatedly conducting FSW [38,53]. The amounts of TiH2 and Al2O3 were 1 mass% and 5 mass% of the mass of ADC12 in the area stirred by the tool. During FSW, the tool rotating speed was 1200 rpm, the tool traversing speed was 120 mm/min, and the tilt angle was 3°. The FSW conditions were determined with reference to previous studies on the fabrication of ADC12 aluminum foam [54]. Next, as is shown in Figure 1c,d, a 15 mm × 15 mm × 6 mm thick precursor was machined from the stirred area by the FSW.

2.2. Precursor Foaming and Press-Forming Method

Figure 2 shows the procedures for continuous foaming and press forming. First, three precursors (referred to as Samples I–III) were placed on the ceramic honeycomb, 150 mm apart from each other. Three halogen lamps were used for heating, each with a current of 9 A and a voltage of 180 V (power consumption of 1620 W). The distance between the top of the precursor and the halogen lamp was 40 mm so that the top surface of the precursor became the focus of the halogen lamp. A robot arm (Single Axis Robots RS2, MISUMI Group Inc., Tokyo, Japan) was used for press forming. The pressing die was an aluminum flat plate of 80 mm × 45 mm × 3 mm thick, and press forming was performed at a press speed of 60 mm/s. First, as is shown in Figure 2a, the first precursor (Sample I) was heated directly under the halogen lamps. After the Sample I precursor foamed, the ceramic honeycomb was moved so that Sample I was directly under the robot arm and the second precursor (Sample II) was directly under the halogen lamps. Then, as is shown in Figure 2b, the press forming of Sample I was performed and the heating of Sample II was started. Next, as is shown in Figure 2c, after the press forming of Sample I was completed and Sample II foamed, the ceramic honeycomb was moved again to press form Sample II, as shown in Figure 2d. The same procedures used for Sample I and Sample II were applied to the third precursor (Sample III), as shown in Figure 2d–f, to perform foaming and press forming continuously. These processes were performed for five trials in this study. It should be noted that after one trial, sufficient time was taken for cooling to be completed before the next trial was performed. For three of the five trials, temperature was measured by a thermocouple from the time the sample was foamed to the end of the press forming. A hole was drilled into the precursor and a thermocouple was inserted so that the tip of the thermocouple touched the center of the precursor. The solidus and liquidus temperatures of the ADC12 aluminum alloy are 515 °C and 580 °C, respectively [55]. For the three trials in which temperatures were measured, heating was stopped when the sample reached 660 °C, and then the sample was moved to just below the pressing die. This temperature was determined as the temperature at which the precursor foams sufficiently and the press forming can be started at a temperature that is higher than the liquidus temperature.

2.3. Evaluation Method

The resulting aluminum foam was subjected to X-ray CT imaging to observe the pore structure. The microfocus X-ray CT (SMX-225CT, Shimadzu Corporation, Kyoto, Japan), was used for the observation with a tube voltage of 80 kV and a tube current of 30 μA. The pixel equivalent length of the X-ray CT images was approximately 75 μm/pixel.
The porosity of the aluminum foam obtained was determined by measuring the density of the aluminum foam using the Archimedes’ method and using the literature value for the density of dense ADC12 aluminum alloy [55]. Porosity is the volume fraction of pores in a sample. The thickness of the aluminum foam obtained was measured at five points using calipers, and the average value was obtained.

3. Results and Discussion

3.1. The Foaming and Press-Forming Processes

Figure 3 shows a video recording of a typical example of the sequential processes of foaming and press forming. The images show entire areas where the samples were foamed and press formed, as well as magnified images of each of the samples. First, as is shown in Figure 3a,b, the precursor of Sample I was placed under halogen lamps to start heating. The time when the heating of Sample I started was set to t = 0 s. As is shown in Figure 3c,d, Sample I can be foamed. Next, the ceramic honeycomb was moved and the foamed Sample I was press formed, as shown in Figure 3e,f, while Sample II was heated as shown in Figure 3e,g. Figure 3h,i show press-formed Sample I. It was found that spherically foamed Sample I can be formed into a flat shape by press forming immediately after foaming. In addition, Sample II can be foamed as shown in Figure 3h,j. Next, the ceramic honeycomb was moved and Sample II was press formed as shown in Figure 3k,l, and Sample III was heated as shown in Figure 3k,m. Figure 3n,o show press-formed Sample II. It was found that the spherically foamed Sample II can be formed into a flat shape by press forming immediately after foaming. In addition, Sample III can be foamed as shown in Figure 3n,p. Finally, the ceramic honeycomb was moved once again, and it was found that Sample III can be press formed into a flat shape as shown in Figure 3q,r. This process was repeated five times, and similar foaming was observed in all three samples, and they were all press formed into a flat shape without fracture in all trials.

3.2. Evaluation Results of the Obtained Aluminum Foam

Photographs and X-ray CT images of each of the three samples obtained by continuous foaming and press forming are shown in Figure 4. Photographs show that a flat aluminum foam can be obtained for all three samples. From the X-ray CT images, it can be seen that in all three samples, there are no areas where the pores have been collapsed and densified by the press-forming process, and pores can be observed throughout the entire samples, indicating that the pores of the aluminum foam are maintained during press forming. Figure 5 shows photographs and X-ray CT images of three samples that were foamed continuously in the same process, except that they were free-foamed without press forming. All three samples can be foamed similarly, and pores can be observed throughout the entire samples. That is, both of the aluminum foams shown in Figure 4 and Figure 5 have pores throughout the entire samples, indicating that aluminum foams with a similar pore structure can be obtained. However, the uniformity of the pore structure requires further investigation of the heating conditions and other factors.
Figure 6 shows the temperature histories of the aluminum foam samples shown in Figure 4 during foaming and press forming. First, the temperature of Sample I increased with heating, and the increase in temperature decreased once the temperature exceeded around 500 °C. This is because the temperature exceeded the solidus temperature and the solid–liquid coexistence state was reached. The temperature rise became rapid again around the liquidus temperature, and the aluminum foam foamed significantly. When the temperature reached 660 °C, the heating was stopped, the press forming was performed, and the sample was then left to cool. Next, the temperature history of Sample II shows a slight increase in temperature before heating due to a slight exposure to light from the halogen lamps during the heating of Sample I. The temperature history was similar to that of Sample I when the sample was moved to directly under the halogen lamps and heating began. Next, the temperature history of Sample III shows that no temperature increase was observed during the heating of Sample I, but during the heating of Sample II, the temperature increased slowly due to a slight exposure to the light from the halogen lamps. The temperature history was similar to that of Samples I and II when the samples were moved to directly under the halogen lamps and heating began. Figure 6 also plots the temperature histories for each sample, showing the temperature at the end of heating, at the start of press forming, and at the end of press forming. It can be seen that the press-forming process started above the liquidus temperature and continued below the solidus temperature until samples solidified properly, even though the continuous process was performed. From these results, it was shown that the temperature histories of the three samples were similar even when the continuous process from foaming to press forming was performed.
Figure 7 shows the temperature histories of the free-foamed samples shown in Figure 5 during foaming. The temperature histories were similar to those in Figure 6, as seen in the press-formed samples, but the temperature decrease from the end of heating was faster and the time of solid–liquid coexistence was shorter for the press-formed samples. The average time from 580 °C to 515 °C was 38.7 s for the press-formed sample and 95.8 s for the free-foaming sample. This means that the cooling time has been reduced from 1/2 to 1/3. This indicates that the cooling rate was enhanced by the contact of the die during the press-forming process. When samples become large, pore raising and pore coarsening cannot be ignored because it takes time for the entire sample to solidify. However, it is expected that these problems can be improved by increasing the cooling rate of the foamed sample by press forming.
A comparison of the porosities of all press-formed samples is shown in Figure 8, which shows the porosities of five trials, with three samples per trial. First, the porosities of the three samples in one trial was similar in all trials, indicating that the similar aluminum foam can be obtained by continuous production. In addition, a comparison of porosities among the five trials showed similar porosities, indicating a high reproducibility. Figure 9 shows the porosities of all free-foamed samples. The porosities of three trials with three samples per trial are shown. As with the press-formed aluminum foam, it can be seen that the porosities are similar from sample to sample. The average and standard deviation of the porosities of all press-formed samples were 77.2% ± 1.7% while those of all free-foamed samples were 78.6% ± 1.3%, indicating that press forming has little effect on the porosity. In addition, the porosities of these aluminum foams are comparable to those of aluminum foams fabricated by the precursor method identified in the literature [1,56].
The sample thicknesses of all the press-formed samples are shown in Figure 10. The thicknesses of three samples are shown for each of the five trials. The average and standard deviation of the sample thicknesses were 8.25 mm ± 0.15 mm. Although there is some variation, it can be seen that almost all of the samples were fabricated with a similar thickness. One of the reasons for the variation in sample thickness is that the samples appear to have shrunk due to solidification after press forming. The temperature gradient during cooling varied slightly from sample to sample and from location to location in the sample, which may have resulted in the variation among the samples. To improve this problem, temperature control of the die is considered to be important and will be an issue to be investigated in the future. Another cause of the variation in the thickness is that the foaming and press forming were performed on the ceramic honeycomb, and the ceramic honeycomb was slightly irregular, which was transferred to the back side of the aluminum foam. This can be solved by using a die with a smooth surface on the bottom. These results indicate that it is possible to form aluminum foam while maintaining the pores by performing press forming immediately after foaming, and that multiple samples can be produced continuously.

3.3. Application to Aluminum Foam with a Wave Shape

In the previous section, we attempted to fabricate flat-shaped aluminum foam using a flat-shaped die. It is expected that aluminum foam of a desired shape can be continuously fabricated by using a complex-shaped die. In this section, we attempted to continuously perform the foaming and press forming of three samples, as in Section 3.1, using a copper pressing die with a wave shape, as shown in Figure 11. A thermocouple was inserted into the sample to measure the temperature during the experiment. As in Section 3.1, heating was stopped at 660 °C, and the press forming was immediately performed until the temperature fell to below the solidus temperature, after which the pressing die was released. Figure 12a shows an image of the heating and press-forming processes. Sample I was press formed and Sample II was heated. In addition, Figure 12b shows an enlarged image of the area where the press forming of Sample I was performed in Figure 12a. The same foaming and press forming as in Section 3.1 could be performed even though the die was changed.
Figure 13 shows photographs and X-ray CT images of three samples obtained by continuous foaming and press forming using the wave-shaped die. Photographs of the three samples show that the two valleys of the die were clearly transferred and two peaks were formed in the wave-shaped aluminum foam. The X-ray CT images show pores in the entire aluminum foam, even in the wave-shaped parts, indicating that the same pore structure was obtained in all three samples.
Figure 14 shows the porosities of the three samples obtained in the three trials, which were performed continuously using the wave-shaped die. The three samples in one trial showed similar porosities, as well as in the three trials. The average porosity and its standard deviation were 74.6% ± 1.8%, indicating that although the porosities were slightly lower than those obtained by press forming into flat shapes or free foaming, aluminum foam with a similar degree of variation could be fabricated. From these results, it is expected that the continuous production of aluminum foam with complex shapes will be possible by continuously performing a sequential process of foaming the precursor and then press forming it.
In this study, the fabrication of one piece of aluminum foam took approximately three to four minutes. This depends on the size of the aluminum foam. It is expected that increasing the power of the heating lamps would enable faster foaming. In addition, increasing the number of heating lamps allows for further higher production speeds. For example, in addition to the heating lamps for foaming, additional lamps for preheating can be provided. The pressing die can also be equipped with a water-cooling mechanism to shorten the cooling time. Therefore, it is expected that this method can produce aluminum foam products of desired shapes with high productivity. In addition, increasing the number of heating lamps would also allow for the production of larger aluminum foam. Furthermore, machine learning has been used to characterize the properties of aluminum foam from nondestructively obtained images by X-ray CT [35]. It is expected that the non-destructive evaluation of the properties of the press-formed aluminum foam will enable the continuous production of the products, including quality assurance.

4. Conclusions

In this study, we attempted to perform a continuous process from the foaming of the precursor to the press forming of aluminum foam for three precursors, with the aim of achieving the continuous production of aluminum foam with desired shapes. The results obtained are shown below.
(1)
It was shown that it is possible to continuously and sequentially foam the precursors by heating and press forming the foamed samples. The continuously obtained aluminum foam samples had a similar shape, porosity, and pore structure.
(2)
The continuously press-formed aluminum foam samples had a similar shape, porosity, and pore structure to those of free-foamed aluminum foam.
(3)
It was shown that aluminum foam with complex shapes can also be continuously fabricated by using a complex-shaped die.
(4)
It was indicated that the use of dies in press forming can shorten the cooling time and reduce the production time approximately from 1/2 to 1/3.
(5)
It will be essential to further investigate the heating and foaming methods to obtain a uniform pore structure in the future.

Author Contributions

Conceptualization, Y.H. and K.A.; investigation, Y.K.; writing—original draft preparation, Y.H. and Y.K.; writing—review and editing, Y.H. and K.A. All authors have read and agreed to the published version of the manuscript.

Funding

This work was financially supported in part by the Light Metal Education Foundation, Mitutoyo Association for Science and Technology (MAST), and Gunma University for the promotion of scientific research.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Fabrication of precursors by FSW. (a) Mixed powder of TiH2 and Al2O3 was sandwiched between ADC12 plates. (b) FSW tool was traversed where the powder mixture was placed. (c) Sample after FSW. (d) Precursor was machined from the stirred area.
Figure 1. Fabrication of precursors by FSW. (a) Mixed powder of TiH2 and Al2O3 was sandwiched between ADC12 plates. (b) FSW tool was traversed where the powder mixture was placed. (c) Sample after FSW. (d) Precursor was machined from the stirred area.
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Figure 2. Procedures for continuous foaming and press forming. (a) Foaming of Sample I. (b) Press forming of Sample I. (c) Foaming of Sample II. (d) Press forming of Sample II. (e) Foaming of Sample III. (f) Press forming of Sample III.
Figure 2. Procedures for continuous foaming and press forming. (a) Foaming of Sample I. (b) Press forming of Sample I. (c) Foaming of Sample II. (d) Press forming of Sample II. (e) Foaming of Sample III. (f) Press forming of Sample III.
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Figure 3. Entire images and enlarged images of each sample for sequential process of foaming and press forming. (a) Entire view of heating Sample I. (b) Enlarged view of heating Sample I. (c) Entire view of foaming Sample I. (d) Enlarged view of foaming Sample I. (e) Entire view of press forming Sample I and heating Sample II. (f) Enlarged view of press forming Sample I. (g) Enlarged view of heating Sample II. (h) Entire view of foaming Sample II. (i) Enlarged view of press formed Sample I. (j) Enlarged view of foaming Sample II. (k) Entire view of press forming Sample II and heating Sample III. (l) Enlarged view of press forming Sample II. (m) Enlarged view of heating Sample III. (n) Entire view of foaming Sample III. (o) Enlarged view of press formed Sample II. (p) Enlarged view of foaming Sample III. (q) Entire view of press forming Sample III. (r) Enlarged view of press forming Sample III.
Figure 3. Entire images and enlarged images of each sample for sequential process of foaming and press forming. (a) Entire view of heating Sample I. (b) Enlarged view of heating Sample I. (c) Entire view of foaming Sample I. (d) Enlarged view of foaming Sample I. (e) Entire view of press forming Sample I and heating Sample II. (f) Enlarged view of press forming Sample I. (g) Enlarged view of heating Sample II. (h) Entire view of foaming Sample II. (i) Enlarged view of press formed Sample I. (j) Enlarged view of foaming Sample II. (k) Entire view of press forming Sample II and heating Sample III. (l) Enlarged view of press forming Sample II. (m) Enlarged view of heating Sample III. (n) Entire view of foaming Sample III. (o) Enlarged view of press formed Sample II. (p) Enlarged view of foaming Sample III. (q) Entire view of press forming Sample III. (r) Enlarged view of press forming Sample III.
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Figure 4. Photographs and X-ray CT images of each of the three samples obtained by continuous foaming and press forming.
Figure 4. Photographs and X-ray CT images of each of the three samples obtained by continuous foaming and press forming.
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Figure 5. Photographs and X-ray CT images of each of the three samples obtained by continuous free foaming without press forming.
Figure 5. Photographs and X-ray CT images of each of the three samples obtained by continuous free foaming without press forming.
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Figure 6. Temperature histories of the aluminum foam samples shown in Figure 4 during foaming and press forming.
Figure 6. Temperature histories of the aluminum foam samples shown in Figure 4 during foaming and press forming.
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Figure 7. Temperature histories of the free-foamed samples shown in Figure 5 during foaming.
Figure 7. Temperature histories of the free-foamed samples shown in Figure 5 during foaming.
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Figure 8. Porosities of all press-formed samples.
Figure 8. Porosities of all press-formed samples.
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Figure 9. Porosities of all free-formed samples without press forming.
Figure 9. Porosities of all free-formed samples without press forming.
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Figure 10. Thicknesses of all press-formed samples.
Figure 10. Thicknesses of all press-formed samples.
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Metals 15 00633 g011
Figure 11. Wave-shaped press forming die.
Figure 11. Wave-shaped press forming die.
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Figure 12. (a) An entire image and (b) an enlarged image of sequential process of foaming and press forming by wave-shaped die.
Figure 12. (a) An entire image and (b) an enlarged image of sequential process of foaming and press forming by wave-shaped die.
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Metals 15 00633 g013
Figure 13. Photographs and X-ray CT images of each of the three samples obtained by continuous foaming and press forming by wave-shaped die.
Figure 13. Photographs and X-ray CT images of each of the three samples obtained by continuous foaming and press forming by wave-shaped die.
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Figure 14. Porosities of all press-formed samples using a wave-shaped die.
Figure 14. Porosities of all press-formed samples using a wave-shaped die.
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Table 1. Chemical composition of JIS ADC12 (mass%).
Table 1. Chemical composition of JIS ADC12 (mass%).
SiFeCuMnMgZnNiSnAl
JIS ADC129.6~12.0<1.31.5~3.5<0.5<0.3<1.0<0.5<0.2Bal.
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Hangai, Y.; Kaneko, Y.; Amagai, K. Continuous Fabrication Process of Aluminum Foam from Foaming to Press Forming. Metals 2025, 15, 633. https://doi.org/10.3390/met15060633

AMA Style

Hangai Y, Kaneko Y, Amagai K. Continuous Fabrication Process of Aluminum Foam from Foaming to Press Forming. Metals. 2025; 15(6):633. https://doi.org/10.3390/met15060633

Chicago/Turabian Style

Hangai, Yoshihiko, Yuito Kaneko, and Kenji Amagai. 2025. "Continuous Fabrication Process of Aluminum Foam from Foaming to Press Forming" Metals 15, no. 6: 633. https://doi.org/10.3390/met15060633

APA Style

Hangai, Y., Kaneko, Y., & Amagai, K. (2025). Continuous Fabrication Process of Aluminum Foam from Foaming to Press Forming. Metals, 15(6), 633. https://doi.org/10.3390/met15060633

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