TY - JOUR
T1 - Effect of defocusing distance on interfacial reaction and mechanical properties of dissimilar laser Al/steel joints with a porous high entropy alloy coating
AU - Jiang, Jiawei
AU - Oliveira, J. P.
AU - Yang, Jin
AU - Zheng, Min
AU - Li, Haoyue
AU - Xu, Wenhu
AU - Wu, Lingqing
AU - Dou, Tianyu
AU - Wang, Ruijun
AU - Tan, Caiwang
AU - Li, Yongbing
N1 - Funding Information:
Financial support of the National Natural Science Foundation of China (52275155 and 5220051748) and Class III Peak Discipline of Shanghai–Materials Science and Engineering (High-Energy Beam Intelligent Processing and Green Manufacturing) are gratefully acknowledged. João Pedro Oliveira acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia , I.P., in the scope of the projects LA/P/0037/2020 , UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication–i3N .
Publisher Copyright:
© 2024 The Authors
PY - 2024/4
Y1 - 2024/4
N2 - Aluminum alloy and low carbon steel were successfully laser weld-brazed when using a porous high entropy alloy (HEA) transient layer. It is shown that the joint wettability increased with the decreasing defocusing distance and the best wettability was obtained at 0 mm defocusing distance with the contact angle of 59.8° and wetting length of 5.57 mm. A fine and dense layer of τ5-(Fe,Co,Cr,Ni)1.8Al7.2Si phase was observed wrapping around the HEA spheres, and its thickness changed in a pronounced way with the defocusing distance, where a maximum thickness of 3.20 μm was obtained at 0 mm. A non-coherent interface and a composite-like structure was formed between the τ5 phase and the HEA spheres. However, the τ5 phase, consisting of a large number of nano-grains, aided in realizing the residual stresses at the joint interface through dislocation slip, leading to an enhanced interfacial bonding and joints failure near the fusion zone. An outstanding fracture load and displacement were achieved, with 333.9 N/mm and 4.07 mm respectively, at the optimized condition of 0 mm defocusing distance. And the mechanism of diffusion and metallurgical evolution was also revealed by thermodynamic calculations and diffusion kinetic analysis.
AB - Aluminum alloy and low carbon steel were successfully laser weld-brazed when using a porous high entropy alloy (HEA) transient layer. It is shown that the joint wettability increased with the decreasing defocusing distance and the best wettability was obtained at 0 mm defocusing distance with the contact angle of 59.8° and wetting length of 5.57 mm. A fine and dense layer of τ5-(Fe,Co,Cr,Ni)1.8Al7.2Si phase was observed wrapping around the HEA spheres, and its thickness changed in a pronounced way with the defocusing distance, where a maximum thickness of 3.20 μm was obtained at 0 mm. A non-coherent interface and a composite-like structure was formed between the τ5 phase and the HEA spheres. However, the τ5 phase, consisting of a large number of nano-grains, aided in realizing the residual stresses at the joint interface through dislocation slip, leading to an enhanced interfacial bonding and joints failure near the fusion zone. An outstanding fracture load and displacement were achieved, with 333.9 N/mm and 4.07 mm respectively, at the optimized condition of 0 mm defocusing distance. And the mechanism of diffusion and metallurgical evolution was also revealed by thermodynamic calculations and diffusion kinetic analysis.
KW - Al/steel dissimilar metals
KW - Defocusing distance
KW - High-entropy alloy
KW - Laser weld-brazing
KW - Mechanical properties
UR - http://www.scopus.com/inward/record.url?scp=85186420797&partnerID=8YFLogxK
U2 - 10.1016/j.matchar.2024.113751
DO - 10.1016/j.matchar.2024.113751
M3 - Article
AN - SCOPUS:85186420797
SN - 1044-5803
VL - 210
JO - Materials Characterization
JF - Materials Characterization
M1 - 113751
ER -