(清華大學(xué) 新材料國際研發(fā)中心，北京 100084)
摘 要: 在變形溫度為150~400 ℃、應(yīng)變速率為0.3~0.000 3 s−1條件下，在Gleeble1500熱模擬機(jī)上采用等溫拉伸試驗(yàn)對AZ31鎂合金鑄軋和常規(guī)軋制板的高溫塑性及組織演變進(jìn)行研究。結(jié)果表明：兩種AZ31鎂合金板的峰值應(yīng)力和峰值應(yīng)變均隨著變形溫度的降低和應(yīng)變速率的增加而逐漸增大。鑄軋板的應(yīng)變硬化指數(shù)和應(yīng)變速率敏感系數(shù)均大于常規(guī)軋制板的。在高溫低應(yīng)變速率變形條件下，鑄軋板的晶界滑移引起的空洞尺寸、體積分?jǐn)?shù)和密度均大于常規(guī)軋制板的。低應(yīng)變速率下拉伸變形后的動態(tài)再結(jié)晶晶粒尺寸隨溫度的升高逐漸增加；不同變形條件下鑄軋板的晶粒尺寸均小于常規(guī)軋制板的；再結(jié)晶晶粒尺寸和Z參數(shù)呈冪律關(guān)系。
關(guān)鍵字: AZ31鎂合金；鑄軋；高溫塑性
normal rolling AZ31 magnesium alloy sheets
（National Center of Novel Materials for International Research, Tsinghua University, Beijing 100084, China）
Abstract:The elevated temperature plasticity and microstructure evolution of cast-rolling and normal rolling AZ31 magnesium alloy sheets were analyzed by Gleeble1500 using tension test with deformation temperature of 150−400 ℃ and strain rate of 0.3−0.000 3 s−1. The results show that the peak stress and peak strain of cast-rolling and normal rolling AZ31 magnesium alloys both increase with decreasing the deformation temperature and increasing the strain rate. The strain hardening exponent value and strain rate sensitivity value of cast rolling sheet are larger than those of normal rolling sheet. Cavity size, volume fraction and density of cast-rolling sheet caused by grain boundary sliding under deformation condition of high temperature and low strain rate are bigger than those of normal rolling sheet. The dynamic recrystallization grain size deformed in low strain rate increases with increasing the deformation temperature. The dynamic recrystallization grain size of cast rolling sheet is less than that of normal rolling sheet. The dynamic recrystallization grain size has power law relation with Z parameter.
Key words: AZ31 magnesium alloy; cast rolling; high temperature plasticity
