Research on laser welding-brazing of dissimilar Mg alloy and stainless steel

Abstract

Laser welding-brazing was developed to join dissimilar AZ31B magnesium (Mg) alloy and AISI304 stainless steel using a high power fiber laser. The maximum joint strength was 211 MPa, which reached 89.8 % of Mg base metal. The interface characterization and fracture behavior of the joints were investigated by employing optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. A transition zone was observed at the interface of fusion zone/steel, where the intermetallic compounds of Mg2Ni and Mg17Al12 were found. The offset from the center of laser beam to the edge of joint seam played a big role in the joining strength by changing the area fraction of reaction layer to whole interface. The smaller the laser offset, the larger the area fraction of reaction layer to whole interface, and thus the stronger the joining strength is. By the characteristics observed on fracture surface, the fracture behavior was summarized.K e y w o r d s : laser brazing, stainless steel, magnesium alloy, interface, tensile strength

A Review of Bonding Immiscible Mg/Steel Dissimilar Metals

“…Laser self-welding only uses a laser source without filling interlayers and filler metals. In one case, the laser melted the Mg alloy, which wets and spreads on the surface of the steel, and forms a brazing joint [31,32,33,34]. In another instance, the laser was focused on the top surface of the steel plate and melted the Mg alloy by thermal conduction heat, thereby forming a brazed joint [35].…”

“…The joint failed at the interface, and the average tensile strength of butt joints reached 185 MPa at 0.6 mm laser offset [32]. Jiang et al also adopted laser welding-brazing to join AZ31B Mg alloy and AISI304 stainless steel [34]. The maximum joint strength was 211 MPa (89.8% Mg base metal) with the laser offset 0.2 mm to Mg alloy side.…”

Power distribution network reliability calculation method based on collective multi-label classifier and energy entropy

“…Therefore, reliability evaluation of the distribution network is essential [1]. So as to achieve the dual-carbon goal, our energy and power will follow the innovative development trend of "clean, comprehensive, intelligent and decentralized" [2]. With the high proportion of distributed generation connected to the grid, it is necessary to break down the failure probability of the new type of distribution system.…”