(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 采用Gleeble−1500熱模擬實驗機進(jìn)行熱壓縮試驗，研究ZA27合金的熱變形行為，在變形溫度為200~ 350 ℃、應(yīng)變速率為0.01~5 s−1、工程應(yīng)變?yōu)?0%，基于Murty準(zhǔn)則，建立ZA27合金的加工圖。結(jié)果表明：流變應(yīng)力隨變形溫度的升高而減小，隨應(yīng)變速率的提高而增大；在變形溫度為200~210 ℃、應(yīng)變速率為0.01~0.1 s−1和變形溫度為250~350 ℃、應(yīng)變速率為1~5 s−1的2個區(qū)域內(nèi)易產(chǎn)生流變失穩(wěn)現(xiàn)象；動態(tài)再結(jié)晶是導(dǎo)致流變軟化及穩(wěn)態(tài)流變的主要原因，ZA27合金的安全熱加工區(qū)域的變形溫度在250~350 ℃之間、應(yīng)變速率在0.1~1 s−1之間。
關(guān)鍵字: ZA27合金；熱變形；加工圖；動態(tài)再結(jié)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
