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研究近α钛合金TA15经等通道转角挤压工艺(ECAP)加工后的维氏显微硬度及其变化规律。结果表明:TA15合金经ECAP挤压后,显微硬度显著提高,且合金试样外层硬度略高于芯部。合金的显微硬度与组织畸变程度、位错密度、晶粒尺寸以及相组成等密切相关。相变点以下挤压,挤压温度越低,硬度越高;相变点以上挤压,由于挤压后水冷过程中在β相内产生针状马氏体α′,硬度明显高于相变点以下挤压。模具转角越小,显微硬度越高。随挤压次数增加,硬度先增大后保持基本不变,而挤压路径对硬度的影响与挤压次数、挤压后细化效果密切相关。TA15合金经ECAP后退火,显微硬度明显降低。
The Vickers microhardness and its variation of near-α titanium alloy TA15 after ECAP process were investigated. The results show that the microhardness of TA15 alloy increases remarkably after ECAP extrusion, and the outer layer hardness of TA15 alloy is slightly higher than that of the core. The microhardness of the alloy is closely related to the degree of tissue distortion, dislocation density, grain size and phase composition. The phase transition point below the extrusion, the extrusion temperature is lower, the higher the hardness; the transformation point above the extrusion, due to squeeze water cooling in the β-phase martensite α ’, the hardness was significantly higher than the phase transition Point the following squeeze. The smaller the mold corner, the higher the microhardness. With the increase of the number of extrusion, the hardness first increases and remains basically unchanged, and the influence of extrusion path on the hardness is closely related to the number of extrusion and the refinement effect after extrusion. TA15 alloy after ECAP annealing, microhardness significantly reduced.