Research

Open AccessArticle

Effect of Cr on the Microstructure and Mechanical Properties of the Al-Cu-Y-Zr Alloy

by

,

,

,

and

Metals 2023, 13(2), 349; https://doi.org/10.3390/met13020349 - 09 Feb 2023

Viewed by 351

Abstract

The present investigation aimed at the determination of Cr addition on microstructure, phase composition, and mechanical properties of the Al-Cu-Y-Zr alloy. Quasi-binary alloys of the ternary Al-Cu-Y system with atomic rotation of Cu/Y = 4/1 have a narrow solidification range with high solidus [...] Read more.

The present investigation aimed at the determination of Cr addition on microstructure, phase composition, and mechanical properties of the Al-Cu-Y-Zr alloy. Quasi-binary alloys of the ternary Al-Cu-Y system with atomic rotation of Cu/Y = 4/1 have a narrow solidification range with high solidus temperature. The addition of 0.3% Cr in the Al-5.1Cu-1.7Y-0.3Zr alloy provides a formation of a novel quaternary Al_81–85Cu_7–10Y_3–4Cr₅ phase. L1₂-Al₃(Zr,Y) phase spherical particles with a diameter of 50 nm were nucleated during solution treatment at 600 °C. Al₇Cr precipitates were not found in the microstructure. The main strengthening effect of 32.4 MPa and 29.1 MPa was achieved from L1₂ and θ’(Al₂Cu) precipitates, respectively, in accordance with the calculation. The calculated hardness of 61.5HV based on the calculated

σ_{y}

is consistent with the experimental value of hardness. Al₃Zr and Al₇Cr phases should be in equilibrium with (Al) in accordance with the calculated polythermal section. However, transmission electron microscopy investigation demonstrates the Al₃(Zr,Y) precipitates only. As a result, the dissolved Cr atom provides a slightly higher hardness in the rolled and annealed AlCuYZrCr alloy. A suitable combination of strength and ductility was observed both after rolling and after rolling with subsequent annealing at 150 °C for 3 h—the alloy exhibited a yield strength of 308–315 MPa, an ultimate tensile strength of 323–335 MPa, and an elongation to failure of 2.0–3.3%. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

Microstructure and Mechanical Properties of Novel Heat Resistant Cast Al-Cu-Yb(Gd)-Mg-Mn-Zr Alloys

by

,

,

,

,

and

Metals 2022, 12(12), 2079; https://doi.org/10.3390/met12122079 - 03 Dec 2022

Cited by 1 | Viewed by 611

Abstract

The present study focused on the development of the novel heat resistant cast Al-Cu-Yb(Gd)-Mg-Mn-Zr alloys based on the prevue investigations. Microstructures and mechanical properties were investigated by optical, scanning and transmission electron microscopy, hardness measurements, and tensile and creep tests at room and [...] Read more.

The present study focused on the development of the novel heat resistant cast Al-Cu-Yb(Gd)-Mg-Mn-Zr alloys based on the prevue investigations. Microstructures and mechanical properties were investigated by optical, scanning and transmission electron microscopy, hardness measurements, and tensile and creep tests at room and elevated temperatures. Ytterbium in combination with Zr and Ti provide greater Al grain refining than gadolinium. The L1₂-Al₃(Zr,Yb) or L1₂-Al₃(Zr,Gd) and Al₂₀Cu₂Mn₃ phase precipitates were nucleated during solution treatment. The average sizes of L1₂-Al₃(Zr,Yb) and L1₂-Al₃(Zr,Gd) are 28 ± 6 nm and 32 ± 4 nm, respectively. Al₂₀Cu₂Mn₃ phase precipitates formed with a more coarse size of 100–200 nm. The highest hardening effect was achieved after 3 h of aging at 210 °C in both alloys due to S’(Al₂CuMg) precipitates. The ultimate tensile strengths (UTS) of the AlCuYbMg and AlCuGdMg alloys at room temperature are 338 and 299 MPa, respectively. The UTS decreases to 220–272 MPa when increasing the temperature of the tensile test to 200–250 °C. The rupture stress at 250 °C for 100 h under stress is 111–113 MPa. The contribution from different structure parts in the yield strength was calculated. The main strengthening effects of 54–60 MPa and 138–153 MPa were achieved from L1₂ and S’ precipitates, respectively. The calculated values of yield strength (YS) are consistent with the experimental data. Novel AlCuYbMg and AlCuGdMg alloys are a potential option for castings for high temperature application. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

Microstructure Refinement by a Combination of Heat Treatment and Thixoforming Process Followed by Severe Plastic Deformation and Their Effects on Al-Si Alloy Hardness

by

Mohamed Abdelgawad Gebril

,

Mohd Zaidi Omar

,

Intan Fadhlina Mohamed

,

Norinsan Kamil Othman

and

Osama M. Irfan

Metals 2022, 12(11), 1972; https://doi.org/10.3390/met12111972 - 18 Nov 2022

Viewed by 528

Abstract

This study fabricated a thixoformed Al-7% Si alloy using the cooling slope technique and subjected it to heat treatment before processing with severe plastic deformation to determine the effect of this combination method on the microstructure refinement and hardness of Al-Si alloys (300 [...] Read more.

This study fabricated a thixoformed Al-7% Si alloy using the cooling slope technique and subjected it to heat treatment before processing with severe plastic deformation to determine the effect of this combination method on the microstructure refinement and hardness of Al-Si alloys (300 Series). Each as-cast and thixoformed Al-Si alloy sample was subjected to equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) individually at room temperature before and after heat treatment. ECAP was conducted in a mould with a 120° channel angle via route A, and HPT was applied with 0.75 and 5 turns. The heat-treated thixoformed Al-Si alloy subjected to the HPT process had an ultra-fine grain microstructure and showed a fine and homogeneous redistribution of the eutectic phase in the Al matrix. For the as-cast alloy, the hardness of the heat-treated thixoformed Al-7% Si alloy increased from 63 HV to 124 and 215 Hv after two ECAP passes and five turns of HPT due to the reduced and redistributed eutectic phase in the Al matrix. Subjecting the Al-7% Si alloy to a combination of semisolid and heat treatment processes before subjecting it to severe plastic deformation resulted in microstructural refinement and improved the hardness of the Al-Si alloy. The results indicate that HPT is a more effective method than ECAP for increasing the hardness of the thixoformed Al-Si alloy due to microstructure refinement. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

Researches on the Macro- and Micro-Structures and Properties of the Vertical Bending Continuous Casted AA6063 Thin Slabs and Their As-Rolled Sheets

by

,

,

,

,

,

,

and

Metals 2022, 12(11), 1937; https://doi.org/10.3390/met12111937 - 12 Nov 2022

Viewed by 621

Abstract

A 6063 aluminum alloy thin slab with a cross-section of 260 × 40 mm² was prepared by a vertical bending continuous casting (VC) process. The effects of homogenization, hot rolling and subsequent heat treatments on the microstructure and properties of the as-cast [...] Read more.

A 6063 aluminum alloy thin slab with a cross-section of 260 × 40 mm² was prepared by a vertical bending continuous casting (VC) process. The effects of homogenization, hot rolling and subsequent heat treatments on the microstructure and properties of the as-cast slabs and as-rolled sheets were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), field emission electron probe (EPMA), macro- and micro-structure observation and tensile tests. The results show that the as-cast structure of AA 6063 was dominated by fine and uniform equiaxed grains. After homogenization, all Mg₂Si phases dissolved back, and the Fe-containing intermetallic phases changed from acicular β-Al₅FeSi phase to spherical α-Al₈Fe₂Si phase. Homogenizing heat treatment before hot rolling can improve the mechanical properties of the alloy. However, in the case of direct rolling without homogenization, the alloy still has good mechanical properties; the strength and plasticity are comparable to that obtained through traditional direct chill (DC) casting, homogenizing and extruding processes, indicating that the VC process has the potential to realize continuous casting and rolling. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

Modelling of Strain-Controlled Thermomechanical Fatigue Testing of Cast AlSi7Cu3.5Mg0.15 (Mn, Zr, V) Alloy for Different Aging Conditions

by

,

,

,

,

and

Metals 2022, 12(8), 1258; https://doi.org/10.3390/met12081258 - 26 Jul 2022

Cited by 1 | Viewed by 801

Abstract

Thermomechanical fatigue loadings (TMF) applied on components in a certain temperature range with a variable state of stress (tensile and/or compression) produce a localized concentration of plastic strains that results in crack initiation and propagation. The time evolution of plastic strains must be [...] Read more.

Thermomechanical fatigue loadings (TMF) applied on components in a certain temperature range with a variable state of stress (tensile and/or compression) produce a localized concentration of plastic strains that results in crack initiation and propagation. The time evolution of plastic strains must be known a priori to predict the lifetime of a part submitted to TMF loadings, which requires an extensive campaign of mechanical characterization conducted at different temperatures and aging conditions. Such a campaign was proposed for the aluminum alloy AlSi7Cu3.5Mg0.15 (Mn, Zr, V), which is recognized as being creep resistant. Combined isothermal low-cycle fatigue and isothermal creep tests were performed on this alloy to determine the constitutive parameters based on the Lemaître and Chaboche (LM&C) viscoplastic model. These laws were implemented within the finite element simulation software (Z-set) to model the response of the alloy to a thermomechanical fatigue test. The results of TMF Z-Set simulations, using the LM&C model adapted for two aging conditions, were then compared with results obtained from “Out of Phase” thermomechanical fatigue testings (OP-TMF) performed on a Gleeble 3800 machine. The modelling of the OP-TMF test revealed the complexity of the mechanical behavior of the material induced by the temperature gradient prevailing along with the cylindrical specimen. It was found that a better prediction of the evolution of plastic strains requires taking into account a larger range of plastic strain rates conditions for the determination of the constitutive law and eventually includes the role of the microstructure in the evolution of the material behavior, starting first with the yield stress. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

The Effect of Ce on the Microstructure, Superplasticity, and Mechanical Properties of Al-Mg-Si-Cu Alloy

by

Andrey G. Mochugovskiy

,

Alexey S. Prosviryakov

,

Nataliya Yu. Tabachkova

and

Anastasia V. Mikhaylovskaya

Metals 2022, 12(3), 512; https://doi.org/10.3390/met12030512 - 17 Mar 2022

Cited by 2 | Viewed by 1240

Abstract

The current study focuses on the influence of Ce on the superplastic behavior, microstructure, and mechanical properties of the Al-Mg-Si-Cu-Zr-Sc alloy. The multilevel microstructural analysis including light, scanning electron, and transmission electron microscopies was carried out. The simple thermomechanical treatment including the hot [...] Read more.

The current study focuses on the influence of Ce on the superplastic behavior, microstructure, and mechanical properties of the Al-Mg-Si-Cu-Zr-Sc alloy. The multilevel microstructural analysis including light, scanning electron, and transmission electron microscopies was carried out. The simple thermomechanical treatment including the hot and cold rolling resulted in fragmentation of the eutectic originated particles of the Ce-bearing phases. The two-step annealing of the ingots provided the precipitation of the L1₂-structured Al₃(Sc,Zr) phase dispersoids with 10 nm mean size and a high number density. Due to the particle stimulated nucleation (PSN) effect caused by the particles of eutectic origin, and Zener pinning effect provided by nanoscale dispersoids of L1₂-structured phases, the studied alloy demonstrated good superplastic properties. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

Effect of Zr on Microstructure and Mechanical Properties of the Al–Cu–Yb and Al–Cu–Gd Alloys

by

,

,

,

,

Andrey G. Mochugovskiy

,

Ruslan Yu. Barkov

and

Andrey V. Pozdniakov

Metals 2022, 12(3), 479; https://doi.org/10.3390/met12030479 - 11 Mar 2022

Cited by 6 | Viewed by 1260

Abstract

The effect of zirconium on the microstructure, phase composition, and mechanical properties of AlCuYb and AlCuGd alloys was studied. The microstructure of the as-cast alloys did not consist of new intermetallic phases of zirconium with other elements, so the zirconium was fully dissolved [...] Read more.

The effect of zirconium on the microstructure, phase composition, and mechanical properties of AlCuYb and AlCuGd alloys was studied. The microstructure of the as-cast alloys did not consist of new intermetallic phases of zirconium with other elements, so the zirconium was fully dissolved in the aluminum matrix. The AlCuYbZr/AlCuGdZr alloys demonstrated higher hardness values compared to the AlCuYb/AlCuGd alloys due to the precipitation of the Al₃(Zr,Yb) and Al₃(Zr,Gd) phases, which were formed during the homogenization treatment. The AlCuYbZr alloy had a 10–20 MPa higher yield and tensile strength than the AlCuGdZr alloy at the same annealing temperature and time. The AlCuYbZr alloy exhibited good mechanical tensile properties at an annealing temperature of 100 °C for 1 h, with a yield strength of 276 MPa, ultimate tensile strength of 312 MPa, and elongation of 3.1%, while the as-rolled AlCuGdZr alloy had similar mechanical tensile properties, with a yield strength of 279 MPa, ultimate tensile strength of 307 MPa, and elongation of 4.8%. At an annealing temperature of 300 °C for 10 min, The AlCuYbZr and AlCuGdZr alloys showed a good ductility of 10.5% and 8%, respectively, with 207 MPa yield strength for both alloys. AlCuYbZr and AlCuGdZr alloys are a prospective base composition for developing novel high technology heat resistant aluminum alloys. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Open AccessArticle

Effect of Grain Refinement on the Dynamic, Mechanical Properties, and Corrosion Behaviour of Al-Mg Alloy

by

,

,

and

Metals 2021, 11(11), 1825; https://doi.org/10.3390/met11111825 - 13 Nov 2021

Cited by 6 | Viewed by 1506

Abstract

In this investigation, aluminium Al-2.5% Mg cast alloy was modified by adding 0.5 Ti and 0.1 B wt % modifiers to investigate their impact on the dynamic behaviour, as well as the mechanical and microstructure properties. The dynamic properties were analysed experimentally using [...] Read more.

In this investigation, aluminium Al-2.5% Mg cast alloy was modified by adding 0.5 Ti and 0.1 B wt % modifiers to investigate their impact on the dynamic behaviour, as well as the mechanical and microstructure properties. The dynamic properties were analysed experimentally using a free vibration impact test and predicted using finite element methods. This study used a high-resolution polarised optical microscope to analyse the microstructure of the studied alloys and X-ray Powder Diffraction (XRD) analysis to determine the developed phases. Microstructure and mechanical properties were mostly enhanced as a result of grain refining during solidification and through the metal segregation process. The microstructure analysis of the modified alloy showed a significant improvement in the grain refinement; hence, the grains were 10 times finer than the cast alloy. The modified Al-2.5% Mg/Ti-B alloy demonstrated reduced inter-granular corrosion (IGC) than the Al-2.5% Mg standard cast alloy. By incorporating Ti-B modifiers into the composition of the cast Al-Mg alloy, the ultimate tensile strength (UTS), strain (ε), and hardness values (HV) were increased by 30.5%, 100%, and 18.18%, respectively. The dynamic properties of the modified alloy showed an enhancement in the resonant (f_n) and damping ratio (ζ) by 7% and 68%, respectively. The predicted resonance frequencies of the investigated alloys showed results close to the experimental dynamic tests. Full article

(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Special Issue "Advances in Casting, Thermomechanical and Heat Treatments of Aluminum Alloy"

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI