(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用Gleeble−1500热模拟实验机进行热压缩试验，研究ZA27合金的热变形行为，在变形温度为200~ 350 ℃、应变速率为0.01~5 s−1、工程应变为60%，基于Murty准则，建立ZA27合金的加工图。结果表明：流变应力随变形温度的升高而减小，随应变速率的提高而增大；在变形温度为200~210 ℃、应变速率为0.01~0.1 s−1和变形温度为250~350 ℃、应变速率为1~5 s−1的2个区域内易产生流变失稳现象；动态再结晶是导致流变软化及稳态流变的主要原因，ZA27合金的安全热加工区域的变形温度在250~350 ℃之间、应变速率在0.1~1 s−1之间。
关键字: ZA27合金；热变形；加工图；动态再结晶
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The hot deformation behavior of ZA27 alloy were investigated by compressive tests on Gleeble−1500 thermal-mechanical simulating tester in the temperatures range of 200−350 ℃, strain rate range of 0.01−5 s−1 and engineering strain of 60%. Based on Murty criterion, the processing map for the ZA27 alloy was obtained. The results show that the flow stress decreases with the increase of temperature, while increases with the increase of strain rate. The flow instability regimes appear at two different regimes: at the temperature of 200−210 ℃and the strain of 0.01−0.1 s−1, as well as at the temperature of 250−350 ℃ and the strain rate of 1−5 s−1. The dynamic recrystallization is the main reason for flow softening and stable flow. The hot deformation of ZA27 alloy can be carried out safely in the region with a strain rate of 0.1−1 s−1 and temperature range of 250−350 ℃.
Key words: ZA27 alloy; hot deformation; processing map; dynamic recrystallization
