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在950-1010℃用GH4169合金的Delta工艺进行应变速率为0.005-0.1 s-1的等温恒应变速率压缩实验,系统研究了δ相对合金热变形行为和微观组织演变的影响。结果表明:初始δ相含量分别为0、3.65%和8.14%的GH4169合金的真应力–真应变曲线均为具有单峰特征的曲线,其本构方程均满足双曲正弦函数,变形激活能分别为441.3、445.8和487.7 kJ/mol;3种合金在热变形过程中的主要软化机制均为动态再结晶;在相同变形条件下,随着δ相含量的增加,动态再结晶临界应变显著降低,再结晶晶粒尺寸减小,再结晶体积分数增大;其中固溶态合金的再结晶形核方式主要为基体γ相的晶界弓弯形核,而预析出δ相的合金中δ相与基体γ相的相界也是再结晶形核的有利位置。由此可见,δ相的存在能促进动态再结晶的发生。
At 950-1010 ℃, the isothermal constant strain rate of 0.005-0.1 s-1 at constant strain rate was experimentally studied by Delta process of GH4169 alloy. The effects of delta relative alloy thermal deformation behavior and microstructure evolution were systematically investigated. The results show that the true stress-true strain curves of GH4169 alloy with initial δ-phase contents of 0, 3.65% and 8.14%, respectively, are curves with unimodal characteristics. The constitutive equations satisfy the hyperbolic sine function and deformation activation energy 441.3, 445.8 and 487.7 kJ / mol, respectively. The main softening mechanisms of the three alloys during dynamic deformation are dynamic recrystallization. Under the same deformation conditions, the critical recrystallization strain decreases remarkably with the increase of δ content, The recrystallization grain size decreases and the recrystallization volume fraction increases. The recrystallization nucleation mode of the solid solution alloy is mainly the grain boundary curvature nuclei of the γ phase of the matrix, and the δ phase and The phase boundary of the matrix γ phase is also a favorable site for recrystallization nucleation. Thus, the presence of δ phase can promote the occurrence of dynamic recrystallization.