鄭海榮1， 王長麗1
(1. 哈爾濱工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，
哈爾濱 150001;
2. 哈爾濱理工大學(xué) 機(jī)械動力工程學(xué)院，
哈爾濱 150008)
摘 要: 對軋制態(tài)MB15鎂合金進(jìn)行了超塑性拉伸實(shí)驗(yàn)， 結(jié)果表明：晶粒尺寸為5.9μm的MB15鎂合金板材, 在溫度為573K、 初始應(yīng)變速率為5.56×10-4s-1的變形條件下，獲得的最大延伸率為309%， 應(yīng)變速率敏感指數(shù)為0.34； 當(dāng)真應(yīng)變?yōu)?.3時(shí)， 試樣的晶粒尺寸為4.5μm，說明在拉伸初始階段軋制鎂合金可以獲得細(xì)晶組織， 同時(shí)發(fā)生了部分動態(tài)再結(jié)晶。 利用掃描電鏡觀察斷口發(fā)現(xiàn)典型的超塑性空洞形貌特征。 通過脹形實(shí)驗(yàn)可以看出，該鎂合金板材的超塑成形性能好，具有良好的超塑性成形應(yīng)用潛力。
關(guān)鍵字: 超塑性； 動態(tài)再結(jié)晶； 氣脹成形； 鎂合金
ZHENG Hai-rong1, WANG Chang-li1
（1.School of Materials Science and Engineering, Harbin Institute of Technology,
Harbin 150001, China;
2.School of Mechanical and Power Engineering, Harbin Science and Technology University, Harbin 150008, China）
Abstract:Superplasticity of a rolled magnesium alloy Mg-Zn-Zr was investigated at 573K and a strain rate of 5.56×10-4s-1. The maximum elongation is 309% and the strain rate sensitivity exponent m is 0.34. The grain size of the rolled magnesium alloy is 5.9μm. However, the grain size of the specimen deformed to a true strain of 0.3 is 4.5μm. The grain refinement is attributed to dynamically continuous recrystallization during the initial stage of tensile test. SEM observation shows that the typical cavities are obvious in fracture surfaces of tensile samples after superplastic deformation. Finally, the successful superplastic gas pressure bulging forming experiment proves the satisfying superplastic forming capability of the alloy.
Key words: superplasticity; dynamic recrystallization; gas pressure bulging; magnesium alloy
