Welding Metallurgy of

Microstructure characteristics and liquation behavior of fiber laser welded joints of Mg-5Zn-1Mn-0.6Sn alloy sheets

Effects of welding current on macromorphologies, microstructures and mechanical properties of nano-SiC particles strengthening activating flux tungsten inert gas welded AZ31 magnesium alloy joints were investigated by scanning electron microscope and energy dispersive X-ray spectrometer observations and microhardness and tensile tests The results showed that SiC particles mainly dwelled in the centre and bottom zone of welding pool Moreover, with the welding current increasing, the mechanical properties of the welding joints were improved by the increased SiC particles in welding pool, the depth/width ratios of weld pool and the refined α-Mg grain size However, the α-Mg grains coarsened and the mechanical properties of joints decreased due to excessive heat input in welding process when welding current over 115 A

Effects of current on nanoparticle reinforced magnesium alloy welding joints

This paper aims at understanding the role of liquation and solidification phenomena on the tensile properties of arc welded cast AZ91 magnesium alloy. Owing to its refined microstructure, the fusio...

Effect of liquation on the tensile properties of cast Mg–9Al–1Zn Alloy fusion welds

As the lightest structural alloys, magnesium alloys offer significant potential for improving the energy efficiency of various transportation systems. The lack of sufficient weldability of Mg alloy...

Critical review on fusion welding of magnesium alloys: metallurgical challenges and opportunities

Fine grained AZ91 sheets of 1 mm in thickness were successfully welded by autogenous laser beam welding and laser beam welding with filler strip. Both welded joints are characterised by fine equiaxed dendrites in the fusion zones and free from significant grain coarsening in the heat affected zones. There are two kinds of liquation reactions in the partially melted zone of the autogenous laser beam welding joint, which are associated with the melting of residual bulky β-Mg17Al12 phase and the constitutional liquation of submicrometre β-Mg17Al12 precipitates. No liquation reaction is detected in the welded joint obtained by laser beam welding with filler strip. The laser beam welding joint with filler strip for AZ91 thin sheets is free from evident collapse.

Q. Zhao

Papers

Microstructural characterisation and liquation behaviour of laser welded joint of fine grained AZ91 magnesium alloy thin sheets