( 1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 西南鋁業(yè)（集團(tuán)）有限責(zé)任公司，重慶 401326)
摘 要: 在Gleeble-1500熱模擬實(shí)驗(yàn)機(jī)上，采用高溫等溫壓縮，0.001~10 s-1，變形溫度為360~520 ℃，對2195鋁-鋰合金在高溫壓縮變形中的流變應(yīng)力行為進(jìn)行了研究，分析了其高溫變形的物理本質(zhì)。結(jié)果表明：在應(yīng)變速率為1 s-1（變形溫度為520 ℃）和應(yīng)變速率為0.1、0.01、0.001 s-1（變形溫度為360~520 ℃）時(shí)，2195鋁-鋰合金熱壓縮變形流變應(yīng)力出現(xiàn)了明顯的峰值應(yīng)力，表現(xiàn)為連續(xù)動(dòng)態(tài)再結(jié)晶特征；在其它變形條件下存在較為明顯的穩(wěn)態(tài)流變特征；可采用Zener-Hollomon參數(shù)的雙曲正弦函數(shù)來描述2195鋁-鋰合金高溫變形時(shí)的流變應(yīng)力行為；在獲得的流變應(yīng)力σ解析表達(dá)式中，A、α和n值分別為2.569×1017 s-1、0.012 48 MPa-1和5.94；熱變形激活能Q為250.45 kJ/mol。
關(guān)鍵字: 2195鋁-鋰合金；熱壓縮變形；流變應(yīng)力；Zener-Hollomon參數(shù)
hot compression deformation
（ 1. School of Materials Science and Engineering,
Central South University, Changsha 410083, China;
2. Southwest Aluminium (Group) Co. Ltd, Chongqing 401326, China）
Abstract: By isothermal compression test at Gleeble-1500 thermal-mechanical simulator, the flow stress behavior of 2195 aluminium-lithium alloy during hot compression deformation was studied with the strain rate rang from 0.001 s-1 to 10 s-1 and the temperature range from 360 ℃ to 520 ℃. The physical essence of hot deformation for 2195 alloy was also studied. The results show that when the strain rate is 1 s-1(the deformation temperature is 520 ℃) and 0.001, 0.01 and 0.1 s-1(360-520 ℃), the flow stress decreases after a peak value, showing continuous dynamic recrystallization. The steady-state flow characteristics exist on the other deformation conditions. The flow stress of 2195 alloy during high temperature deformation can be expressed by a Zener-Hollomon parameter in the hyperbolic sine function. The values of A, α and n in the analytical expressions of flow stress(σ) are fitted to be 2.569×1017 s-1, 0.012 48 MPa-1 and 5.94. The hot deformation activation energy of 2195 alloy during hot deformation is 250.45 kJ/mol.
Key words: 2195 aluminum-lithium alloy; hot compression deformation; flow stress; Zener-Hollomon parameter
