Microstructure and mechanical properties of hot extruded solid materials from rapidly solidified AZ9 Article Abstract
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Published: January 30, 2006
The hot extrusion of AZ91D alloy solid materials 14 mm in diameter were prepared from single-roller rapidly solidif-ied(RS)ribbons at 330 ℃.In order to reveal the microstructure evolution during hot extrusion,OM,SEM,TEM and XRD apparatuses were used at each processing step.The experimental results show that the RS ribbons were welded very well after hot extrusion.The ultimate tensile strength(UTS)and the yield strength(YTS)increased 55.9% and 77.6% respectively than that of as-cast ingot,the elongation(E%)is almost the same and the hardness(HV and HB)is greatly improved.After heat treatment,UTS and YTS of RS bars did not change obviously,the E% improved 5.6 times.A little amount of β-Mg17Al12 com-pound,the product of precipitation from the supersaturated á-Mg solid solution,dispersed inside the á-Mg grains during the RS ribbons hot extrusion,which became more during the bars'heat treatment,and the fracture appeared in ductility.It is co-ncluded that the strength of the extruded materials from RS ribbons depends on the microstructures of RS as well as the extru-sion processes.