Dissimilar material laser welding between magnesium alloy AZ31B and aluminum alloy A5052-O

TLDR

Joining technology of lightweight dissimilar metals between magnesium and aluminum alloys is essential for realizing hybrid structure cars and other engineering applications. The study aims to identify a method to control molten metal penetration depth and width to regulate intermetallic layer thickness. The authors employed FEM heat‑transfer analysis to guide laser welding, first using normal center‑line lap joints and then edge‑line lap joints to control intermetallic layer thickness. Edge‑line welding guided by FEM analysis produced a thinner intermetallic layer and achieved high joining strength, whereas normal center‑line welding suffered from a thick intermetallic layer that degraded strength.

Abstract

Joining technology of lightweight dissimilar metals between magnesium and aluminum alloys is essential for realizing hybrid structure cars and other engineering applications. In the present study, the normal center-line welding of lap joint was carried out by laser welding. It was found that the intermetallic layer formed near interface between two metals significantly degraded the joining strength. FEM heat transfer analysis was carried out to find out an available method to control penetration depth and width of molten metal, which contributes to control thickness of intermetallic compound layer. Based on the results of FEM analysis, the edge-line welding of lap joint was carried out, which could easily control the thickness of intermetallic layer and successfully obtained high joining strength.