Papers by Keyword: Cross-Tensile Strength

Abstract: This study was carried out to newly develop the fluxes and filler metals for brazing magnesium alloy AZ31B more easily at lower temperatures. Furthermore, surface preparation was developed to improve the brazeability of magnesium alloy. The main results obtained are as follows. We could successfully develop the fluxes that consisted of chlorides containing Ca ion and Li ion, which made the faying surface of the magnesium alloy active at around 450°C. In addition, we succeeded in developing the filler metals with the melting temperatures lower than 490°C which were Mg-Sn-In system containing a small amount of Al to lower the melting temperature. Surface preparation for magnesium alloy by immersion in aqueous solution containing halogen ion improved remarkably the brazeability of the magnesium alloy. Using the surface preparation together, the fluxes and filler metals could achieve the brazed joints with a high strength equivalent to that of the base metal.

Abstract: We tried to join steel to Al-Mg alloy using a resistance spot welding method. The effect of Mg in Al-Mg alloy on the strength and the interfacial microstructure of the joint was investigated. Additionally, the effect of insert metal of commercially pure aluminum, which was put into the bonding interface, on the joint strength was examined. The obtained results were as follows. The cross-tensile strength of a joint between SS400 steel and commercially pure aluminum (SS400/Al) was high and fracture occurred in the aluminum base metal. However, the strength of a joint between SS400 and Al-Mg alloy was remarkably low and less than 30% of that of the SS400/Al joint. An intermetallic compound layer developed so thickly at the bonded interface of the SS400/Al-Mg alloy joint that the joint strength decreased. The intermetallic compound layer developed more thickly as Mg content in the Al-Mg alloy increased. Using insert metal of commercially pure aluminum containing little Mg successfully improved the strength of the SS400/Al-Mg alloy joint and the strength was equivalent to that of the base metal.