The Effect of Additional element Zr on Solid Solubility of Cr and mechanical Properties of Rapidly Solidifified Al - Cr Alloys
김종렬Jong Ryoul Kim, 김동훈Tong Hoon Kim
Abstract
A study was carried out on the microstructure and the mechanical properties of Al-Cr and Al-Cr-Zr alloy splats produced by atomization-splat-quenching method and their extruded bars. Two types of microstructure were observed on the etched cross sections of the splats: the first type was composed of microcrystallines and fine cellular dendrites (zone A) and the other contained large amount of intermetallic compounds (zone B). When Zr was added to Al-Cr alloy, the maximum solid solubility of Cr extended from 5 wt % to 8 wt % and the relative amount of zone A also increased. In comparison to Al-Cr alloy, the maximum peak hardness of the Al-Cr-Zr alloy was higher and the thermal stability was also increased. An isothermal aging of extruded bars at 350℃ of 100 hours did not affect hardness significantly.