Papers by Keyword: Mg Alloy Sheets

Abstract: The yield locus of type AZ31 magnesium alloy sheet was obtained by performing biaxial tensile tests, using cruciform specimens, at temperatures of 100, 150, 200, 250 and 300 P o PC at strain rates of 10P -2 P, 10P -3 P and 10P -4 PsP -1 P. Based on the experimental results, the effects of strain-rate and temperature on the yield locus was discussed. The size of yield locus drastically decreased with increasing temperature and decreased with decreasing strain-rate. Neither von Mises’s criterion or Hill’s can well predict the shape of the yield locus of this sheet metal. Instead of these quadratic yield functions, the yield criterion of Logan-Hosford or Barlat is a better choice for the accurate description of biaxial stress-strain responses at high temperature.

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: AZ31 and experimental ZMA611 alloys were strip cast into 2 mm thick strips. The as-cast AZ31 alloy strip consists of columnar dendrites. On the other hand, as-cast ZMA611 alloy strip shows equiaxed dendritic structure through the thickness of strip. These alloys were subjected to various thermomechanical treatments and their tensile properties were evaluated. Strip cast AZ31 alloy in H24 condition has equivalent yield and tensile strengths with similar ductility compared to commercial ingot cast AZ31-H24 alloy, indicating that strip casting is a viable process for the fabrication of Mg alloy strips. The ZMA611 alloy has a large volume fraction of fine dispersoid particles in the microstructure, resulting from the beneficial effect of strip casting on microstructural refinement. It has been shown that the ZMA611 alloy has superior tensile properties compared to commercial ingot cast AZ31-H24 alloy, suggesting the possibility of the development of new wrought Mg alloy sheets by strip casting.