热处理对网状结构TiBW/Ti60复合材料组织与性能的影响
Effects of heat treatment on microstructure and properties of TiBW/Ti60 composites with network microstructure

使用大尺寸球形Ti60钛合金粉与细小TiB2粉, 通过低能球磨与反应热压烧结, 成功制备了增强相呈网状分布的TiB晶须增强Ti60合金基(TiBW/Ti60)复合材料.对TiBW/Ti60复合材料进行热处理, 以改善其组织结构与力学性能.结果表明: 随着固溶温度的升高, TiBW/Ti60复合材料基体中初生α相(密排六方相)含量减少, 相应地转变β组织(α'(马氏体)+残留β相(体心立方相))含量增加, TiBW/Ti60复合材料的抗拉强度升高, 塑性降低;经过1 100 ℃/1 h固溶处理之后, TiBW/Ti60复合材料的室温抗拉强度为1 470 MPa, 延伸率为1.9%.经过时效处理后, 转变β组织中的α'相分解成细小α+β相.经过1 100 ℃/1 h固溶+600 ℃/8 h时效处理后TiBW/Ti60复合材料的硬度达到HV538, 抗拉强度达到1 552 MPa, 延伸率为1.5%, 经过1 000 ℃/1 h固溶+600 ℃/8 h时效处理, 其抗拉强度达到1 460 MPa, 延伸率为2.2%. TiB whiskers reinforced Ti60 alloy matrix (TiBW/Ti60) composites with the reinforcement distributing as network microstructure were successfully fabricated by using large spherical Ti60 alloy powders and fine TiB2 powders and processes of low energy milling and reactive hot pressingsintering. Heat treatment was performed on TiBW/Ti60 composites to improve their microstructure and mechanical properties. The results show that the fraction of the primary α phase (hexagonal closepacked phase)in TiBW/Ti60 matrix decreases while that of the transformed β microstructure including α' (martensite) and residual β phase (body-centered cubic phase) increases with increasing solid solution temperatures. Therefore, the tensile strength of TiBW/Ti60 composites increases while the ductility decreases with increasing solid solution temperatures. After solid solution by 1 100 ℃/1 h, the tensile strength of TiBW/Ti60 composites is 1 470 MPa at room temperature along with an elongation of 1.9%. The α' phase in the transformed β microstructure translates into fine α+β phases after aging process. After solid solution by 1 100 ℃/1 h followed by aging at 600 ℃ for 8 h,the hardness of TiBW/Ti60 composites reaches to HV538 and the tensile strength increases to 1 552 MPa along with an elongation of 1.5%.After solid solution by 1 000 ℃/1 h followed by aging at 600 ℃ for 8 h,the tensile strength increases to 1 460 MPa along with an elongation of 2.2%. 国家"863"计划(2013AA031202);国家自然科学基金(51101042,51271064,51471063);中央高校基本科研业务费专项资金(HIT.BRETIII.201401)