超高压力对ZA27合金非平衡凝固组织和性能的影响

Effect of Super-high Pressure on the Non-equilibrium Solidified Microstructure and Mechanical Properties of ZA27 Alloy

研究了高压凝固条件下ZA27合金凝固组织的变化。高压凝固ZA27合金的宏观组织为致密的网状结构,每个晶粒由相互平行的二次枝晶所构成,而且二次枝晶具有一定的方向性,最后凝固组织并非(β+η)共晶体,而是单一的η相,高压也增加了Zn在α相以及Al在η相中的固溶度。同时高压使ZA27合金的二次枝晶臂间距(DAS)减小,硬度获得大幅度的提高。

The structures of the ZA27 alloy solidified under high pressure (25 GPa) have been investigated. The netlike macrostructure is obtained for ZA27 alloy solidified under high pressure,and each crystallite consisted of secondary dendrites. The solidification is completed by formation of η phase instead of!the eutectic (β+η) structure. The solid solubility of Zn in η phase and Al in α phase is increased largely by high pressure. At the same time the high pressure make the DAS of ZA27 alloy decreased and the hardness increased largely.