原位自生(Ti_(5)Si_(3)+TiB_(w))/TC11复合材料组织与力学性能

Microstructures and mechanical properties of in-situ(Ti_(5)Si_(3)+TiB_(w))/TC11 composites

基于热力学计算和Hashin-Shtrikman理论,结合球磨和热等静压方法,制备出原位自生增强体呈准连续网状分布的(Ti_(5)Si_(3)+TiB_(w))/TC11复合材料。结果表明:(Ti_(5)Si_(3)+TiB_(w))/TC11复合材料由α-Ti、β-Ti、Ti_(5)Si_(3)和TiB_(w)相组成;TC11基体由片状α相和β相组成,为魏氏组织;原位自生的TiB_(w)呈准连续网状分布于TC11基体周围;Ti_(5)Si_(3)增强相一部分分布在TiB_(w)附近,一部分分布在β-Ti内,Ti_(5)Si_(3)的形成主要经历原位自生、高温固溶和脱溶析出等过程。对(Ti_(5)Si_(3)+TiB_(w))/TC11复合材料力学性能分析表明,与TC11基体相比,(4Ti_(5)Si_(3)+5TiB_(w))/TC11复合材料的洛氏硬度提高了约55%,(2Ti_(5)Si_(3)+5TiB_(w))/TC11复合材料的抗压强度和抗拉强度最高,分别为1910 MPa和1105 MPa,主要与TiB_(w)、Ti_(5)Si_(3)增强“晶界”、相界,阻碍位错运动有关。

Based on the thermodynamic calculation and Hashin-Shtrikman theory,in situ(Ti_(5)Si_(3)+TiB_(w))/TC11 composites with a quasi-continuous network microstructure were successfully fabricated by ball milling and hot isostatic pressing.The results show that(Ti_(5)Si_(3)+TiB_(w))/TC11 composites are composed ofα-Ti,β-Ti,Ti_(5)Si_(3)and TiB_(w)phases.The TC11 matrix is composed of flakeαphases andβphases,which is Widmannstatten structure.In-situ TiB_(w)is distributed in a quasi-continuous network around the TC11 matrix.In addition,Ti_(5)Si_(3)phases are partially distributed near TiB_(w),and partly distribute in theβ-Ti.The formation of Ti_(5)Si_(3)mainly includes in situ autogenesis,high-temperature solid solution and desolation precipitation.The analysis of mechanical properties of(Ti_(5)Si_(3)+TiB_(w))/TC11 composites shows that compared with the TC11 matrix,the Rockwell hardness of the(4Ti_(5)Si_(3)+5TiB_(w))/TC11 composite is improved by about 55%,and the compressive strength and tensile strength of the(2Ti_(5)Si_(3)+5TiB_(w))/TC11 composite are the highest,1910 MPa and 1105 MPa,respectively.This can be attributed to the"grain boundaries"and phase boundaries that enhanced with TiB_(w)and Ti_(5)Si_(3)reinforcements hindering dislocation motion.