摘要
研究了固溶处理对经5年自然时效的触变成形ZA27合金硬度的影响,并应用扫描电镜(SEM)和XRD对金相显微组织做了进一步的研究。结果表明:在360℃下固溶处理24h后,合金的微观组织由近球状的初生粒子(黑色)和晶间的二次凝固组织转变为单一的β相。固溶处理对合金硬度的影响则是原始强化相η相的溶解与稳定的β相不断析出的综合结果。固溶处理开始几小时后,由于原始强化相的溶解,材料的硬度下降,而后随着固溶时间的增加,强化相的不断析出,硬度不断提高,当到一定的程度,组织出现了过饱和的亚稳态,硬度又开始降低。
Abstract.The effect of solution treatment on the hardness of the thixoformed ZA27 alloy after natural aging for 5 years has been studied. The microstructure has been observed by SEM and XRD resulting in that the microstructure of the alloy became into polygonal β phase particles from spherical primary particles （in black） and interparticle secondarily solidified structures after solid solution treatment at 360℃ for 24h.Theeffect of solution treatment on hardness of the alloy was the result of the solution of the hard brittle η phase and precipitation of β phase. The longer the solution time was, and the more the solution of the hard brittle η phase was, and the hardness decrease continuously. When the solution time was 〉4h, the precipitate speed of the β phase might increase, so the increase in the hardness with solution time changed from slow to sudden. To some extent the improvement was stopped and then the hardness began to decrease.
出处
《中国铸造装备与技术》
CAS
2011年第1期13-16,共4页
China Foundry Machinery & Technology
