On the metallurgical challenges of intermetallic compound in steel/Al dissimilar resistance spot welding: significance, growth and controlling mechanisms

ABSTRACT

A lightweight multi-material combination of steel and aluminium alloy is becoming a novel approach towards environmentally sustainable transport systems. However, the joining of steel/Al is difficult due to the formation of brittle and hard intermetallic compounds (IMC) at the interface. Hence, there is an immense need to critically review the metallurgical challenges of IMC formation for steel/Al dissimilar RSW and summarise its significance and current scenario for controlling IMC formation and growth. This article presents the review of past research works that focus on controlling the formation and growth of IMC for steel/Al dissimilar resistance spot welding during the last decade. It also includes IMC formation mechanism, advanced characterisation techniques, significance of IMC thickness and effect of process parameters on IMC formation. Fe₂Al₅ is the most brittle and dominant IMC formed at the interface, which affects the soundness of the welded joint. Application of third-party interlayer at the interface, directly or by an auxiliary process, is observed as an effective approach for controlling the growth of IMC. Though this interlayer does not prevent the formation of IMC, it will reduce the growth or brittleness of IMC by changing its chemical configuration.

KEYWORDS:

• RSW
• dissimilar welding
• intermetallic compound
• interlayer
• Fe₂Al₅

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Gujarat Council on Science and Technology (GUJCOST), Gujarat, India (Grant number GUJCOST/STI/2021-22/3832)