Cu-0.4Zr-0.15Y合金动态再结晶临界条件

Critical conditions of dynamic recrystallization of the Cu-0.4Zr-0.15Y alloy

利用Gleeble-1500D型热模拟试验机对Cu-0.4Zr-0.15Y合金进行高温单次轴向热压缩试验,研究该合金在应变速率范围为0.001~10 s^(-1),热变形温度为550~900℃条件下的热变形行为。通过真应力-真应变数据得出材料的加工硬化率θ,结合lnθ-ε曲线和-(lnθ)/ε-ε曲线特征,研究Cu-0.4Zr-0.15Y合金热变形过程的再结晶临界条件。结果表明:Cu-0.4Zr-0.15Y合金应力-应变具有动态再结晶特征;该合金的lnθ-ε曲线拐点处对应于-(lnθ)/ε-ε曲线的最小值,最小值所对应的应变是临界应变ε_c;临界应变ε_c的变化与应变速率和变形温度有关,临界应变ε_c与Zener-Hollomon参数Z之间的函数关系为ε_c=6.4×10^(-3)Z^(0.07768),且临界应变ε_c与峰值应变ε_p之间满足ε_c/ε_p=0.448。同时,Cu-0.4Zr-0.15Y合金发生动态再结晶组织演变与变形温度和应变速率有关。

The high temperature single axial hot compression test of the Cu-0.4Zr-0. 15Y alloy was carried out on a Gleeble-1500D thermal simulator. The thermal deformation behavior of the Cu-0.4Zr-0. 15Y alloy was studied under the strain rate range of 0. 001-10 s -1 and the thermal deformation temperature from 550 ℃ to 900 ℃. Material hardening rate θ of the alloy was obtained by the true stress-true strain data. The recrystallization conditions of the Cu-0.4Zr-0. 15Y alloy during hot deformation process were studied according to the curves of inθ - ε and - （lnθ）/ ε -ε. The results indicate that the Cu-0.4Zr-0.15Y alloy exhibits the feature of dynamic reerystallization in the process of the hot compression test. The inflection point of the Inθ-ε curve corresponds to the minimum of the - （lnθ）/ ε - ε curve. The strain corresponding to the minimum value of the - （lnθ）/dε - ε curve is the critical strain （εc） of the Cu-0.4Zr-0.15Y alloy. The change of critical strain is related to strain rate and deformation temperature. The model function relationship between critical strain εc and Zener-Hollomon parameter （Z） is described by the function of εc = 6.4 × 10-3 Z0 07768. There is a relationship between the critical strain εc and the peak strain εp, i. e. εc/εp = 0. 448. The dynamic recrystallization process of the Cu-0.4Zr-0.15Y alloy is related to the deformation temperature and strain rate.