等温压缩对钛合金TC4-DT组织及断裂韧性的影响
Effects of Isothermal Compression on Microstructure and Fracture Toughness of TC4-DT Titanium Alloy
彭小娜, 郭鸿镇, 石志峰, 姚泽坤
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作者单位：西北工业大学 材料学院， 陕西 西安 710072
中文关键字：损伤容限型钛合金； 显微组织； TC4-DT； 断裂韧性
英文关键字：damage tolerance titanium alloy; microstructure; TC4-DT; fracture toughness
中文摘要：研究了不同温度等温压缩变形及热处理后对损伤容限型钛合金TC4-DT断裂韧性的影响，对比分析了各个温度下的显微组织与断裂韧性的关系，用扫描电镜对断口进行了观察。研究结果表明，两相区较低温度等温压缩变形得到等轴组织，较高温度得到双态组织； 相变点以上得到片层组织，片状组织的断裂韧性高于等轴组织。 4种温度的断口均为等轴韧窝型延性断裂，随着温度的升高，断面粗糙度增加，韧窝直径和深度逐渐下降，在片层组织中发现了二次裂纹。
英文摘要：The influences of isothermal deformation at different temperature on fracture toughness of damage tolerance titanium alloy TC4-DT were studied. The microstructure and fracture toughness were compared and analyzed. The fracture surface was investigated by SEM. The results show that, when deformation is in the lower region of the two phase, equiaxial α phase can be obtained, while in the higher region, bi-modal microstructure can be acquired. The fracture toughness of lamellar microstructure is higher than that of equiaxial microstructure when deformed above the phase transition. The fracture at every temperature is equiaxed dimple-type ductile fracture. With the increase of temperature, the roughness of fracture surfaces increases and the diameter and depth of dimple decrease. Secondary cracks are observed in the lamellar microstructure.