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采用Gleeble—3500热模拟压缩试验机对TA15钛合金进行等温恒应变速率压缩实验,并应用材料分析测试技术(XRD与TEM)和相关定量计算理论(XRD线形傅氏分析法)分析其热压缩变形过程中的位错演化。结果表明,TA15钛合金热压缩变形过程中位错类型主要为柱面(1010)、基面(0002)、锥面(1011)和(110)β面位错,位错密度均在1013~1014 cm-2范围内。当变形温度为950℃且变形量为40%时,随着应变速率的提高,柱面(1010)和(110)β面位错密度几乎不变;当变形量升至60%时,随应变速率的提高,各晶面的位错密度均显著降低。当应变速率为1s-1时,随变形量的增加,平均晶格应变和位错密度均减小;当变形量为60%时,晶格应变降到0.116%~0.138%,位错密度减小到(1.1~1.7)×1014 cm-2。在(α+β)两相区出现了由位错形成的“微观变形带”及位错胞结构;在β单相区板条状马氏体α’相内部位错密度较低,形成位错塞积群,且在位错塞积群和马氏体α’相之间形成高度的应力集中。
The isothermal constant strain rate compression experiments of TA15 titanium alloy were carried out by Gleeble-3500 thermal simulation compressive testing machine. The hot compressive deformation was analyzed by XRD and TEM Dislocation evolution during the process. The results show that the dislocation types of TA15 titanium alloy during hot compression deformation mainly consist of cylinder surface (1010), basal plane (0002), cone (1011) and (110) β surface dislocations with dislocation densities of 1013 ~ 1014 cm-2 range. When the deformation temperature is 950 ℃ and the deformation is 40%, the dislocation density of cylinder (1010) and (110) β hardly change with the increase of strain rate. When the deformation increases to 60% With the increase of the rate, the dislocation density of each crystal plane is significantly reduced. When the strain rate is 1s-1, the average lattice strain and dislocation density decrease with the increase of deformation amount. When the deformation amount is 60%, the lattice strain decreases to 0.116% -0.138%, and the dislocation density decreases As small as (1.1 ~ 1.7) × 1014 cm-2. In the (α + β) two-phase region, the “microscopic deformation band” and the dislocation cell structure formed by dislocations appear. The dislocation density in the lamellar martensite α ’ A dislocation plug cluster is formed, and a high concentration of stress is formed between the dislocation plug cluster and the martensite α ’phase.