Investigating the influence of Ni interlayers on Fe/Al laser welded joints: A first-principles study
Haoyue Wu, Guang Yang, Yue Li, Yue Li, Min Lei, Xuewen Li, Yulong Li, Yulong Li
Abstract
201 Stainless steel and 5052 aluminium alloy were laser lap welded, both with and without a Ni foil interlayer. The Ni addition enhanced the metallurgical reaction between molten stainless steel/aluminium, resulting in the formation of the Al0.9Ni1.1 intermetallic compound. First-principles calculations estimated the equilibrium lattice and properties of IMCs (intermetallic compounds). A structural model of the interface revealed that the bonding strengths of Al/IMC and Fe/IMC interfaces surpassed those of IMC/IMC interfaces, making cracks prone to initiate and expand at the latter. Joints without Ni reached a max tensile shear strength of 74.5 N/mm, while those with Ni increased significantly to 101.8 N/mm, marking a substantial 36.6% enhancement.