# Analysis on Bonding Interface during Solid State Additive Manufacturing between 18Cr-8Ni and 42CrMo4 High Performance Alloys

^{1}

^{2}

^{3}

^{4}

^{5}

^{6}

^{7}

^{8}

^{9}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Design of Experiments

## 3. Materials and Methods

## 4. Mathematical Model

_{0}+ a

_{1}FP+ a

_{2}UP + a

_{3}BOL + a

_{12}FP × UP + a

_{13}FP × BOL + a

_{23}UP × BOL + a

_{11}FP

^{2}+ a

_{22}UP

^{2}+ a

_{33}BOL

^{2}

_{0}is the average of output responses and a

_{1}, a

_{2}a

_{3}…a

_{33}are the response coefficients which are dependent on the effect of input parameters. Based on the DOE, the significance of the model and the combination of welding parameters with output responses are confirmed by using p values. The values of p less than 5% (0.05) indicate significant models. Whereas, the p values greater than 0.05 are insignificant models. A two-factor interaction model, 2FI, is utilised for the sequential sum of squares for the two-factor interaction such as FP, UP or UP and BL, etc. While using a linear model, the F-value tests the significance of adding interaction terms. The p value of the linear model is 0.76 and of the 2FI model is 0.61; both are suggested as near matching models. However, for the quadratic vs. 2FI model, the p value is 0.0028, which is suggested and significant for the present model. Among three welding parameters, the friction force is an essential factor to relate the combination with other factors and also significant with the second order form. Parameters for optimal strength have been predicted with the help of the ANOVA optimization method, with tensile strength and friction welding parameters serving as inputs. The 2D and 3D response surface graphs were created to display the results with the link between input parameters and tensile strength. Moreover, the data of the prediction by mathematical model and the actual data comparison showed good fitting with the model to form a linear relation with the regression of 1.

## 5. Results and Discussion

#### Optimization

^{−4}× FP × UP − 1.86 × FP × BOL − 5.51 × UP × BOL − 1.06 × FP

^{2}− 3.81 × UP

^{2}− 0.11 × BOL

^{2}

## 6. Conclusions

- The mathematical models obtained to correlate the effect of friction process parameters in the bond strength using response contour graphs.
- The bond strength is significantly affected by the friction force and burn-off length. Tensile strength is identified as increasing with the increasing of friction pressure and burn-off length up to optimal values, after which it started to decrease.
- Above the critical point, the intermixing zone widened as the burn-off length increased, indicating a weakening of the bonds.
- Due to the interplay of the bands, the maximum hardness was achieved near the interface. The fractography results showed that there were no brittle phases present, indicating that the fracture happened in a ductile manner.
- The additive manufacturing process in the solid state results in deposits with a low wall resolution. Mixing zones where elemental bands migrate in opposite directions to generate microstructures at interfaces.
- The structure property correlations, linearity of the deposition and defects analysis are considered as a future interests.

## Author Contributions

## Funding

## Data Availability Statement

## Conflicts of Interest

## References

- Paventhan, R.; Lakshminarayanan, P.R.; Balasubramanian, V. Optimization of friction welding process parameters for joining carbon steel and stainless steel. J. Iron Steel Res. Int.
**2012**, 19, 66–71. [Google Scholar] [CrossRef] - Muralimohan, C.H.; Ashfaq, M.; Ashiri, R.; Muthupandi, V.; Sivaprasad, K. Analysis and characterization of the role of Ni interlayer in the friction welding of titanium and 304 austenitic stainless steel. Metall. Mater. Trans. A
**2016**, 47, 347–359. [Google Scholar] [CrossRef] - Yi, M.-S. Comparison of welding deformation characteristics by circumferential welding for austenitic and duplex stainless steel pipe: Experimental Study. J. Weld. Join.
**2022**, 40, 141–148. [Google Scholar] [CrossRef] - Muthupandi, V.; Srinivasan, P.B.; Seshadri, S.K.; Sundaresan, S. Effect of weld metal chemistry and heat input on the structure and properties of duplex stainless steel welds. Mater. Sci. Eng. A
**2003**, 358, 9–16. [Google Scholar] [CrossRef] - Cheepu, M.; Susila, P. Interface microstructure characteristics of friction-welded joint of titanium to stainless steel with interlayer. Trans. Indian Inst. Met.
**2020**, 73, 1497–1501. [Google Scholar] [CrossRef] - Kong, Y.S.; Cheepu, M.; Park, Y.W. Effect of heating time on thermomechanical behavior of friction-welded A105 bar to A312 pipe joints. Trans. Indian Inst. Met.
**2020**, 73, 1433–1438. [Google Scholar] [CrossRef] - Cheepu, M.; Che, W.S. Friction welding of titanium to stainless steel using Al interlayer. Trans. Indian Inst. Met.
**2019**, 72, 1563–1568. [Google Scholar] [CrossRef] - Sathiya, P.; Panneerselvam, K.; Abdul Jaleel, M.Y. Optimization of laser welding process parameters for super austenitic stainless steel using artificial neural networks and genetic algorithm. Mater. Des.
**2011**, 32, 1253–1261. [Google Scholar] [CrossRef] - Cheepu, M.; Che, W.S. Influence of friction pressure on microstructure and joining phenomena of dissimilar joints. Trans. Indian Inst. Met.
**2020**, 73, 1455–1460. [Google Scholar] [CrossRef] - Sahin, M. Evaluation of the joint interface properties of Austenitic stainless steel joined by friction welding. Mater. Des.
**2007**, 28, 2244–2250. [Google Scholar] [CrossRef] - Cheepu, M.; Muthupandi, V.; Che, W.S. Interface microstructural characterization of titanium to stainless steel dissimilar friction welds. In Proceeding of the TMS 2019 148th Annual Meeting & Exhibition, San Antonio, TX, USA, 10–14 March 2019; Springer Publisher: Cham, Switzerland, 2019; pp. 259–268. [Google Scholar]
- Faes, K.; Dhooge, A.; De Baets, P.; Van Der Donckt, E.; De Waele, W. Parameter optimisation for automatic pipeline girth welding using a new friction welding method. Mater. Des.
**2009**, 30, 581–589. [Google Scholar] [CrossRef] - Cheepu, M.; Venkateswarlu, D.; Rao, P.N.; Muthupandi, V.; Sivaprasad, K.; Che, W.S. Microstructure characterization of superalloy 718 during dissimilar rotary friction welding. Mater. Sci. Forum
**2019**, 969, 211–217. [Google Scholar] [CrossRef] - Jung, J.-H.; Park, D.-W.; Baek, E.-R. Study on the Microstructure and Mechanical Properties of Butt GMAW Al/Fe Dissimilar Joints using Pure Copper Filler Metal. J. Weld. Join.
**2021**, 39, 641–648. [Google Scholar] [CrossRef] - Cheepu, M.; Muthupandi, V.; Che, W.S. Improving mechanical properties of dissimilar material friction welds. Appl. Mech. Mater.
**2018**, 877, 157–162. [Google Scholar] [CrossRef] - Kong, Y.S.; Cheepu, M.; Lee, J.K. Evaluation of the mechanical properties of Inconel 718 to SCM 440 dissimilar friction welding through real-time monitoring of the acoustic emission system. Proc. Inst. Mech. Eng. Pt. L J. Mater. Des. Appl.
**2021**, 235, 1181–1190. [Google Scholar] [CrossRef] - Cheepu, M.; Venkateswarlu, D.; Rao, P.N.; Kumaran, S.S.; Srinivasan, N. Effect of process parameters and heat input on weld bead geometry of laser welded titanium Ti-6Al-4V alloy. Mater. Sci. Forum
**2019**, 969, 613–618. [Google Scholar] [CrossRef] - Chandra, G.R.; Venukumar, S.; Cheepu, M. Influence of rotational speed on the dissimilar friction welding of heat-treated aluminum alloys. IOP Conf. Ser. Mater. Sci. Eng.
**2020**, 998, 012070. [Google Scholar] [CrossRef] - Gopi, S.; Mohan, D.G. Evaluating the Welding Pulses of Various Tool Profiles in Single-Pass Friction Stir Welding of 6082-T6 Aluminium Alloy. J. Weld. Join.
**2021**, 39, 284–294. [Google Scholar] [CrossRef] - Muralimohan, C.H.; Muthupandi, V.; Sivaprasad, K. The influence of aluminum intermediate layer in dissimilar friction welds. Int. J. Mater. Res.
**2014**, 105, 350–357. [Google Scholar] [CrossRef] - Aali, M. Investigation of Spindle Rotation Rate Effects on the Mechanical Behavior of Friction Stir Welded Ti 4Al 2V Alloy. J. Weld. Join.
**2020**, 38, 81–91. [Google Scholar] [CrossRef] [Green Version] - Paventhan, R.; Thirumalaikumarasamy, D.; Kantumuchu, V.C.; Ahmed, O.S.; Abbas, M.; Alahmadi, A.A.; Alwetaishi, M.; Alzaed, A.N.; Ramachandran, C.S. Optimizing Friction Welding Parameters in AISI 304 Austenitic Stainless Steel and Commercial Copper Dissimilar Joints. Coatings
**2023**, 13, 261. [Google Scholar] [CrossRef] - Anuradha, M.; Das, V.C.; Venkateswarlu, D.; Cheepu, M. Parameter optimization for laser welding of high strength dissimilar materials. Mater. Sci. Forum
**2019**, 969, 558–564. [Google Scholar] [CrossRef] - Lee, J.M.; Cheepu, M.; Chung, H. Experiment-Based Distortion Prediction Model for Wire-Based Additive Manufactured Parts. J. Mech. Sci. Technol.
**2022**, 36, 6227–6237. [Google Scholar] [CrossRef] - James, J.A.; Sudhish, R. Study on effect of interlayer in friction welding for dissimilar steels: SS 304 and AISI 1040. Procedia Technol.
**2016**, 25, 1191–1198. [Google Scholar] [CrossRef] - Cheepu, M.; Susila, P. Growth rate of intermetallics in aluminum to copper dissimilar welding. Trans. Indian Inst. Met.
**2020**, 73, 1509–1514. [Google Scholar] [CrossRef] - Kong, Y.S.; Cheepu, M.; Kim, D.G. Microstructure and Mechanical Properties of Friction-Welded and Post-Heat-Treated Inconel 718. Trans. Indian Inst. Met.
**2020**, 73, 1449–1453. [Google Scholar] [CrossRef] - You, H.; Lee, T.; Kang, M.; Kim, C. Process Review on Dissimilar Metal Joining of Steel and Ti Alloys. J. Weld. Join.
**2021**, 39, 666–676. [Google Scholar] [CrossRef] - Kang, S.; Cha, J.; Kang, M. A Review on the Design Rule for the Friction Stir Welding using Bobbin Tool for Aluminum. J. Weld. Join.
**2021**, 39, 520–526. [Google Scholar] [CrossRef] - Haribabu, S.; Cheepu, M.; Devuri, V.; Kantumuchu, V.C. Optimization of welding parameters for friction welding of 304 stainless steel to D3Tool steel using response surface methodology. In Techno-Societal 2018: Proceedings of the 2nd International Conference on Advanced Technologies for Societal Applications, Maharashtra, India, 14–15 December 2018; Springer International Publishing: Cham, Switzerland, 2020; Volume 1, pp. 427–437. [Google Scholar]
- Anuradha, M.; Das, V.C.; Susila, P.; Cheepu, M.; Venkateswarlu, D. Effect of welding parameters on TIG welding of Inconel 718 to AISI 4140 steel. Trans. Indian Inst. Met.
**2020**, 73, 1515–1520. [Google Scholar] [CrossRef] - Lee, J.-H.; Park, H.-K. Evaluation of WC-Co-Cr3C2 Hard Materials for Friction Stir Welding Tool Application via Spark Plasma Sintering Process. J. Weld. Join.
**2021**, 39, 513–519. [Google Scholar] [CrossRef] - Haribabu, S.; Cheepu, M.; Tammineni, L.; Gurasala, N.K.; Devuri, V.; Kantumuchu, V.C. Dissimilar Friction Welding of AISI 304 Austenitic Stainless Steel and AISI D3 Tool Steel: Mechanical Properties and Microstructural Characterization. In Advances in Materials and Metallurgy; Lecture Notes in Mechanical Engineering; Lakshminarayanan, A., Idapalapati, S., Vasudevan, M., Eds.; Springer: Singapore, 2019. [Google Scholar]
- Venkateswarlu, D.; Cheepu, M.; Rao, P.N.; Kumaran, S.S.; Srinivasan, N. Characterization of microstructure and mechanical properties of AA2219-O and T6 friction stir welds. Mater. Sci. Forum
**2019**, 969, 205–210. [Google Scholar] [CrossRef] - Cheepu, M.; Cheepu, H.; Che, W.S. Influence of Joint Interface on Mechanical Properties in Dissimilar Friction Welds. Adv. Mater. Process. Technol.
**2022**, 8, 732–744. [Google Scholar] [CrossRef] - Anuradha, M.; Das, V.C.; Susila, P.; Cheepu, M.; Venkateswarlu, D. Microstructure and mechanical properties for the dissimilar joining of Inconel 718 alloy to high strength steel by TIG welding. Trans. Indian Inst. Met.
**2020**, 73, 1521–1525. [Google Scholar] [CrossRef] - Bang, H.-S.; Bang, H.-S.; Kim, K.-H. Effects of Process Parameters on Friction Stir Weldability in Dissimilar Joints of AA5052 and Advanced High Strength Steel. J. Weld. Join.
**2021**, 39, 189–197. [Google Scholar] [CrossRef] - Lakshiminarayanan, A.K.; Balasubramanian, V. Comparison of RSM with ANN in predicting tensile strength of friction stir welded AA7039 aluminum alloy joints. Trans. Nonferrous Met. Soc. China.
**2009**, 19, 9–18. [Google Scholar] [CrossRef] - Bakkiyaraj, M.; Saikrishnan, G.; Balasubramanian, V. Estimating the mechanical properties of friction welded AISI 410 MSS joints using empirical relationship. Metallur. Res. Technol.
**2020**, 117, 618. [Google Scholar] [CrossRef] - Palanivel, R.; Laubscher, R.F.; Dinaharan, I. An investigation into the effect of friction welding parameters on tensile strength of titanium tubes by utilizing an empirical relationship. Measurement
**2017**, 98, 77–91. [Google Scholar] [CrossRef] - Kimura, M.; Suzuki, K.; Kusaka, M.; Kaizu, K. Effect of friction welding condition on joining phenomena and mechanical properties of friction welded joint between 6063 aluminium alloy and AISI 304 stainless steel. J. Manuf. Process.
**2017**, 26, 178–187. [Google Scholar] [CrossRef] - Hakan, A. Prediction of gas metal arc welding parameters based on artificial neural networks. Mater. Des.
**2007**, 28, 2015–2023. [Google Scholar] - Luo, J.; Ye, Y.H.; Xu, J.J.; Luo, J.Y.; Chen, S.M.; Wang, X.C.; Liu, K.W. A new mixed-integrated approach to control welded flashes forming process of damping-tube–gland in continuous drive friction welding. Mater. Des.
**2009**, 30, 353–358. [Google Scholar] [CrossRef] - Oh, D.; Kang, Y.; Kim, K. Effect of Additive Machines and Powders on Mechanical Properties of Stainless Steel 316L Manufactured by L-PBF. J. Weld. Join.
**2022**, 40, 322–328. [Google Scholar] [CrossRef] - Xian, G.; Cheepu, M.; Yu, J.; Cho, S.M.; Yeom, J.T.; Choi, Y.S.; Kang, N. Enhancing Tensile Properties of Wire-Arc Additively Manufactured Ti-6Al-4 V Deposits Via Cryogenic Vaporised Ar Shielding/Cooling. Met. Mater. Int.
**2023**, 29, 501–514. [Google Scholar] [CrossRef] - Kantumuchu, V.C.; Cheepu, M. The Influence of Friction Time on the Joint Interface and Mechanical Properties in Dissimilar Friction Welds. J. Met. Mater. Res.
**2022**, 5, 1–7. [Google Scholar] [CrossRef] - Cheepu, M.; Che, W.S. Effect of Burn-off Length on the Properties of Friction Welded Dissimilar Steel Bars. J. Weld. Join.
**2019**, 37, 46–55. [Google Scholar] [CrossRef] - Park, J.; An, G.; Kim, D. Residual Stress and Deformation Characteristics by FSW and SAW of Wear Resistant Steel. J Weld Join.
**2022**, 40, 133–140. [Google Scholar] [CrossRef] - Kantumuchu, V.C. Additive Manufacturing for Industrial Applications and Potential Quality Challenges. In Advances in Additive Manufacturing Processes; Bentham Science Publishers: Bussum, The Netherlands, 2021; pp. 216–239. [Google Scholar]
- Shiva, A.; Cheepu, M.; Kantumuchu, V.C.; Kumar, K.R.; Venkateswarlu, D.; Srinivas, B.; Jerome, S. Microstructure characterization of Al-TiC surface composite fabricated by friction stir processing. In IOP Conference Series: Materials Science and Engineering; IOP Publishing: Bristol, UK, 2018; Volume 330, p. 012060. [Google Scholar]
- Kavitha, C.; Malini, P.G.; Kantumuchu, V.C.; Kumar, N.M.; Verma, A.; Boopathi, S. An experimental study on the hardness and wear rate of carbonitride coated stainless steel. In Materials Today: Proceedings; Elsevier: Amsterdam, The Netherlands, 2022. [Google Scholar]
- Sarila, V.K.; Koneru, H.P.; Pathapalli, V.R.; Cheepu, M.; Kantumuchu, V.C. Wear and Microstructural Characteristics of Colmonoy-4 and Stellite-6 Additive Layer Deposits on En19 Steel by Laser Cladding. Trans. Indian Inst. Met.
**2022**, 1–8. [Google Scholar] [CrossRef] - Cheepu, M.; Kantumuchu, V.C. Numerical Simulations of the Effect of Heat Input on Microstructural Growth for MIG-Based Wire Arc Additive Manufacturing of Inconel 718. Trans. Indian Inst. Met.
**2022**, 1–9. [Google Scholar] [CrossRef] - Sarila, V.K.; Moinuddin, S.Q.; Cheepu, M.; Rajendran, H.; Kantumuchu, V.C. Characterization of Microstructural Anisotropy in 17–4 PH Stainless Steel Fabricated by DMLS Additive Manufacturing and Laser Shot Peening. Trans. Indian Inst. Met.
**2022**, 1–8. [Google Scholar] [CrossRef] - Sarila, V.; Koneru, H.P.; Cheepu, M.; Chigilipalli, B.K.; Kantumuchu, V.C.; Shanmugam, M. Microstructural and Mechanical Properties of AZ31B to AA6061 Dissimilar Joints Fabricated by Refill Friction Stir Spot Welding. J. Manuf. Mater. Process.
**2022**, 6, 95. [Google Scholar] [CrossRef] - Cheepu, M.; Venukumar, S.; Phanindra, K.H.; Likhith, N.; Sameer, M.; Johith, M.S.; Devuri, V.; Kantumunchu, C. Optimization of welding parameters for the joint interface of rotary friction welds. In AIP Conference Proceedings; AIP Publishing LLC: Melville, NY, USA, 2022; Volume 2648, p. 030035. [Google Scholar]
- Cheepu, M.; Baek, H.J.; Kim, Y.S.; Cho, S.M. Penetration Estimation of GTAW with C-Type Filler by Net Heat Input Ratio. Weld. J.
**2022**, 101, 240s–248s. [Google Scholar] [CrossRef]

**Figure 2.**The linear graphs shows the developed response model accuracy conditions (

**a**) Normal plot of residuals, (

**b**) predicted and experimental values comparison.

**Figure 4.**The effect of welding conditions on tensile strength graphs (

**a**,

**c**,

**e**) Contour plots (2D), and (

**b**,

**d**,

**f**) are response surface graphs (3D).

**Figure 10.**Fractography analysis of the tensile tested joints of the failure location (

**a**) 42CrMo4 and (

**b**) 18Cr-8Ni.

**Figure 14.**Solid state additive manufacturing of dissimilar layers (

**a**) as deposited, (

**b**) wall resolution processed condition.

**Figure 15.**Interface microstructure of the solid state additive manufacturing of dissimilar layers at different intermixing zones (burn-off length) (

**a**) 2 mm, (

**b**) 4 mm and (

**c**) 6 mm.

Welding Conditions | Minimum Level | Maximum Level |
---|---|---|

Friction pressure (MPa) | 80 | 140 |

Upset Pressure (MPa) | 160 | 220 |

Burn-off length (mm) | 1 | 6 |

Substrate Type | C | Si | Mn | P | S | Ni | Cr | Mo | N | Fe |
---|---|---|---|---|---|---|---|---|---|---|

42CrMo4 | 0.41 | 0.17 | 0.82 | 0.036 | 0.038 | - | 1.05 | 0.23 | - | balance |

Cr18-Ni8 | 0.03 | 0.85 | 1.6 | 0.045 | 0.03 | 8.2 | 17.68 | 3.4 | 0.1 | balance |

Substrate Type | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (Hv) | Melting Temperature (°C) |
---|---|---|---|---|---|

42CrMo4 | 687 | 415 | 28 | 210 | 1416 |

Cr18-Ni8 | 716 | 593 | 39 | 220 | 1440 |

Run | Code of Factors | Welding Conditions | Tensile Strength (MPa) | ||||
---|---|---|---|---|---|---|---|

Low | Middle | High | FP (MPa) | UP (MPa) | BOL (mm) | - | |

1 | 1 | −1 | 0 | 140 | 160 | 3 | 502.74 |

2 | −1 | 1 | 0 | 80 | 220 | 3 | 563.52 |

3 | 0 | −1 | 1 | 110 | 160 | 6 | 548.05 |

4 | 0 | 0 | 0 | 110 | 190 | 3 | 571.58 |

5 | 0 | 0 | 0 | 110 | 190 | 3 | 572.65 |

6 | −1 | 0 | −1 | 80 | 190 | 1 | 469.56 |

7 | 1 | 0 | −1 | 140 | 190 | 1 | 530.56 |

8 | −1 | −1 | 0 | 80 | 160 | 3 | 479.5 |

9 | −1 | 0 | 1 | 80 | 190 | 6 | 486.5 |

10 | 0 | 0 | 0 | 110 | 190 | 3 | 572.56 |

11 | 1 | 0 | 1 | 140 | 190 | 6 | 510.58 |

12 | 0 | 1 | 1 | 110 | 220 | 6 | 520.34 |

13 | 0 | −1 | −1 | 110 | 160 | 1 | 498.65 |

14 | 1 | 1 | 0 | 140 | 220 | 3 | 509.47 |

15 | 0 | 1 | −1 | 110 | 220 | 1 | 540.58 |

16 | 0 | 0 | 0 | 110 | 190 | 3 | 575.89 |

17 | 0 | 0 | 0 | 110 | 190 | 3 | 576.48 |

**Table 5.**Analysis results of the significance of each order and determination of the order of response model.

Source | Sum of Squares | DOF | Mean Square | F Value | p-Value Prob > F | Significance |
---|---|---|---|---|---|---|

Mean vs. Total | 8343.77 | 1 | 9018.84 | - | - | Suggested |

Linear vs. Mean | 4.89 | 3 | 0.29 | 0.40 | 0.7586 | - |

2FI vs. Linear | 2.65 | 3 | 0.50 | 0.62 | 0.6172 | - |

Quadratic vs. 2FI | 11.89 | 3 | 2.27 | 13.26 | 0.0028 | Suggested & Significant |

Cubic vs. Quadratic | 4.27 | 3 | 0.40 | 188.41 | <0.0001 | - |

Residual | 3.56 | 4 | 2.105 × 10^{−3} | - | - | - |

Total | 8371.03 | 17 | 531.13 | - | - | - |

Source | Sum of Squares | DOF | Mean Square | F Value | p-Value Prob > F | Significance |
---|---|---|---|---|---|---|

Model | 9.17 | 9 | 1.02 | 5.95 | 0.0141 | Significant |

A-FP | 0.34 | 1 | 0.34 | 1.99 | 0.2009 | - |

B-UP | 0.85 | 1 | 0.85 | 4.97 | 0.0610 | - |

C-BOL | 0.15 | 1 | 0.15 | 0.90 | 0.3738 | - |

AB | 0.72 | 1 | 0.72 | 4.18 | 0.0802 | - |

AC | 0.080 | 1 | 0.080 | 0.47 | 0.5166 | - |

BC | 0.70 | 1 | 0.70 | 4.07 | 0.0834 | - |

A^{2} | 3.84 | 1 | 3.84 | 22.41 | 0.0021 | - |

B^{2} | 0.50 | 1 | 0.50 | 2.89 | 0.1328 | - |

C^{2} | 1.88 | 1 | 1.88 | 11.01 | 0.0128 | - |

Residual | 1.20 | 7 | 0.17 | - | - | - |

Lack of fit | 1.19 | 3 | 0.40 | 188.41 | <0.0001 | Significant |

Pure error | 8.419 × 10^{−3} | 4 | 2.105 × 10^{−3} | - | - | - |

Cor Total | 10.37 | 16 | - | - | - | - |

**Table 7.**Optimal response model analysis based on the value of accuracy and R-squared value of fitting curves.

Std. | Adjusted | R-Squared | Predicted | Std. Dev. | Press | Significance |
---|---|---|---|---|---|---|

Source | R-Squared | R-Squared | ||||

Linear | 0.85 | 0.08 | −0.12 | −0.52 | 15.82 | - |

2FI | 0.89 | 0.22 | −0.23 | −1.38 | 24.72 | - |

Quadratic | 0.41 | 0.88 | 0.73 | −0.82 | 18.95 | Suggested |

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Moinuddin, S.Q.; Machireddy, V.V.; Raghavender, V.; Kaniganti, T.B.; Sarila, V.; Ponnappan, S.M.; Shanmugam, R.; Cheepu, M.
Analysis on Bonding Interface during Solid State Additive Manufacturing between 18Cr-8Ni and 42CrMo4 High Performance Alloys. *Metals* **2023**, *13*, 488.
https://doi.org/10.3390/met13030488

**AMA Style**

Moinuddin SQ, Machireddy VV, Raghavender V, Kaniganti TB, Sarila V, Ponnappan SM, Shanmugam R, Cheepu M.
Analysis on Bonding Interface during Solid State Additive Manufacturing between 18Cr-8Ni and 42CrMo4 High Performance Alloys. *Metals*. 2023; 13(3):488.
https://doi.org/10.3390/met13030488

**Chicago/Turabian Style**

Moinuddin, Syed Quadir, Venkata Varalakshmi Machireddy, Vadla Raghavender, Tejonadha Babu Kaniganti, Venukumar Sarila, Shankar Madhuraveli Ponnappan, Ragavanantham Shanmugam, and Muralimohan Cheepu.
2023. "Analysis on Bonding Interface during Solid State Additive Manufacturing between 18Cr-8Ni and 42CrMo4 High Performance Alloys" *Metals* 13, no. 3: 488.
https://doi.org/10.3390/met13030488