Abstract:
TiB whiskers reinforced Ti60 alloy matrix (TiB
W/Ti60) composites with the reinforcement distributing as network microstructure were successfully fabricated by using large spherical Ti60 alloy powders and fine TiB
2 powders and processes of low energy milling and reactive hot pressingsintering. Heat treatment was performed on TiB
W/Ti60 composites to improve their microstructure and mechanical properties. The results show that the fraction of the primary α phase (hexagonal closepacked phase)in TiB
W/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 TiB
W/Ti60 composites increases while the ductility decreases with increasing solid solution temperatures. After solid solution by 1 100 ℃/1 h, the tensile strength of TiB
W/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 TiB
W/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%.