Investigation of Microstructural Features and Mechanical Performance in Wire Arc Additive Manufactured Dissimilar Metal Cladding of Mild Steel (ER70S-6) and Aluminium Alloy (Al-4043)
摘要
This study explores dissimilar metal cladding of Al-4043 on ER70S-6 using an in-house Dual-Wire Gas Tungsten Arc Welding-based Wire Arc Additive Manufacturing process. It addresses the challenge of brittle Fe3Al intermetallic formation at the interface by optimizing welding parameters (welding current, arc voltage, and welding speed) through the Taguchi method and analysis of variance to control the thickness of intermetallic compounds (IMCs). SEM-EDS analysis revealed IMC thickness variations from 5.63 to 175.70 µm, influenced by the heat input of different process parameters. Optimized parameters, including an 80 A welding current, 10 V arc voltage, and a welding speed of 600 mm/min, resulted in a minimal IMC thickness of 5.77 µm, as confirmed through validation tests. Using these parameters, a 20 mm-high, 4 mm-thick Al-4043 wall was deposited on a 20 mm-high, 4 mm-thick ER70S-6 wall and subsequently characterized by microhardness measurements, XRD, and tensile testing. Hardness at the interface spikes to 282 HV due to IMC, while ER70S-6 (165-181 HV) and Al-4043 (85-125 HV) remain stable. The Fe3Al region exhibits an ultimate tensile strength of 207 MPa and a yield strength of 186 MPa, but with a low elongation of 13.5%. These findings suggest strong metallurgical bonding, making this cladding approach promising for aerospace and automotive applications.