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对Al-2.5Cu-1.58Li-0.3Mn-0.12Zr-0.06Mg-0.05Ti(质量分数,%)合金进行连续、不连续、双道次和多道次热压缩,研究其力学行为和微观组织演化。采用Gleeble-1500试验机对合金进行热变形,变形温度为420℃,应变速率分别为0.001,0.1和10 s~(-1),对合金不同热变形阶段进行EBSD和TEM分析。双道次热压缩表明,道次间隔时间的延长有利于促进静态软化。通过改变变形过程中的应变速率,可控制合金的晶粒尺寸。多道次热变形过程中,道次间的静态软化促进动态软化,反之亦然。在多道次热变形过程中(T=420℃,ε=0.1 s~(-1))出现T_1和θ′相动态析出。变形初始阶段,应变诱导的位错为T_1和θ′相提供形核位置,促进它们的析出和粗化。随应变的增加,T_1和θ′相尺寸减小并趋于稳定,δ′相密度降低。试验合金多道次热变形过程中的流变应力受动态软化、静态软化和动态析出综合影响。
The mechanical behavior and microstructure of Al-2.5Cu-1.58Li-0.3Mn-0.12Zr-0.06Mg-0.05Ti (mass fraction) alloy were investigated by continuous, discontinuous, evolution. The Gleeble-1500 testing machine was used to heat-deform the alloy. The deformation temperature was 420 ℃, and the strain rates were 0.001, 0.1 and 10 s -1 respectively. The EBSD and TEM analyzes of the alloy during different hot deformation stages were carried out. Two-pass thermal compression shows that the prolongation of the pass interval is conducive to the promotion of static softening. By changing the strain rate during deformation, the grain size of the alloy can be controlled. During multi-pass thermal deformation, static softening between passes promotes dynamic softening and vice versa. In the multi-pass thermal deformation process (T = 420 ℃, ε = 0.1 s ~ (-1)), T_1 and θ ’phases appear. In the initial stage of deformation, strain induced dislocations provide nucleation sites for the T_1 and θ ’facies to promote their precipitation and coarsening. With the increase of strain, the size of T_1 and θ ’decreases and tends to be stable, and the density of δ’ phase decreases. The flow stress in multi-pass hot deformation of test alloy is affected by dynamic softening, static softening and dynamic precipitation.