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用原位自生技术制备了TiB增强的近α相钛基复合材料,利用金相显微镜、高温材料试验机和透射电镜(TEM)研究了热加工过程中此复合材料的魏氏组织演变和TiB晶须的取向变化,并测定了该复合材料的力学性能。研究结果表明:该复合材料的β晶粒尺寸和α片层的厚度随着压下率的增加而减小,这种变化使复合材料的显微组织得到了显著细化;随着压下率的增加,延伸方向上TiB晶须取向角的小角度概率密度值急剧增加,而大角度概率密度值急剧减小,加工方向上TiB晶须的概率密度值变为原来的6倍左右;热机械加工后该复合材料较之原来的铸态材料状态,屈服强度增加了25%左右,抗拉强度增加了30%左右,时效后屈服强度和抗拉强度都提高44%左右;若没有硅化物的析出,片层状α相的厚度值b对强度的影响较小,时效后硅化物沉淀析出使厚度值b成为重要的强化因素。
The TiB-reinforced near-α-phase titanium matrix composites were prepared by in-situ techniques. The microstructure evolution and TiB crystal structure of the composites were investigated by metallographic microscope, high temperature material testing machine and transmission electron microscopy (TEM) The change of the orientation required, and measured the mechanical properties of the composite material. The results show that the β grain size and the thickness of the α sheet decrease with the increase of the reduction rate. The microstructure of the composite material is significantly refined. With the reduction rate , The small-angle probability density value of TiB whisker orientation angle sharply increases while the large-angle probability density value sharply decreases in the extending direction, and the probability density value of TiB whiskers in the processing direction becomes about 6 times of the original value. The thermal mechanical After processing, compared with the original as-cast material, the yield strength of the composite increased by about 25%, the tensile strength increased by about 30%, and the yield strength and tensile strength increased by about 44% after aging. Without the silicide The thickness b of the lamellar α phase is less affected by the precipitation. After the aging, precipitation of silicide precipitates the thickness b as an important strengthening factor.