Microstructure and mechanical properties of Ti-TiBw-x%Cu composites by powder metallurgy using atomized Ti-TiBw powder as raw materials

Titanium matrix composites (TMCs) reinforced with titanium boride whisker (TiBw) prepared by conventional smelting or powder metallurgy via in-situ techniques are inevitable to cause TiBw coarsening by hightemperature thermal history, which feasibly leads to stress concentration and results in seriously inverse relationship between strength and toughness. This paper developed a novel strategy using Ti-TiBw composite powder as raw powder which is produced by the plasma rotating electrode atomization method (PREP), to control TiBw to nanoscale size by taking advantage of the rapid cooling rate of PREP. On this basis, the fast eutectic element Cu was proposed as alloying element and introduced into Ti-TiBw composite system using powder metallurgy, to investigate the influence rules of Cu content on TiBw scale characteristic parameters (diameter and aspect ratio, etc.) as well as the microstructure and mechanical properties of Ti-TiBw composites. The hardness of the specimen was increased by 61.9%, while its tensile strength and yield strength were increased to 823 & PLUSMN; 12 MPa and 602 & PLUSMN; 11 MPa, respectively. Its elongation retained the same level at 10.8 & PLUSMN; 1.9% as that of Ti-TiBw composites.

Automated summary

This study developed a novel method to control the size of titanium boride whiskers through the use of Ti-TiBw composite powder produced by the plasma rotating electrode atomization method. The addition of copper as an alloying element in the Ti-TiBw composite system through powder metallurgy was investigated to determine its effect on the size parameters, microstructure, and mechanical properties of the composites. The results showed that the hardness of the specimens increased by 61.9%, while their tensile strength and yield strength also increased significantly, with no significant change in elongation.