Effect of Heat Treatment Temperature on Microstructure and Hardness of Zr-9 mol%Au Near-Eutectoid Alloy

Abstract

In order to develop new functional biomaterials, the Zr Au alloy system was focused and a Zr 9 molAu near eutectoid alloy was used in this work. Effect of solution treatment and aging treatment temperatures on phase constituent, microstructure and Vickers hardness was investigated. It was found that Zr 9 molAu is a hypereutectic composition and experimental results in this work are not in agreement with the experimental phase diagram reported by Lomello Tafin et al., but in good agreement with the calculated phase diagram reported Su et al. The major apparent phase was hcp aZr regardless of the heat treatment condition and Zr 3 Au second phase precipitated when heat treated at 1173 K or lower temperatrues. The Vickers hardness value was HV503 after the solution treatment at 1273 K, but became lower with increasing the amount of micrometer size Zr 3 Au precipitates. The hardness of this alloy was mainly due to the amount of the solute Au in aZr matrix. However, the alloy was slightly hardened by aging at 673 K due to the formation of submicron meter size fine Zr 3 Au precipitates.

A Review of Investigations on Microstructure and Mechanical Properties of the Present Achievements of the Ti-Au-based Shape Memory Alloys

“…Besides to the thermal stability and phase constituent issues, the workability of the materials, which is also a crucial prerequisite for practical uses, is also necessary to be considered. It was discovered that, opposite to the Zr-4Au alloys possessing poor workability, the Ti-4Au alloys performed excellent workability, 22,23) which is beneficial for the synthesis of the biomedical materials with certain dimensions and shapes.…”