Microstructure and mechanical properties of Ti6Al4V/ B4C titanium matrix composite fabricated by selective laser melting (SLM)

Abstract

x wt.% B4C/Ti6Al4V titanium matrix composites were prepared by selective laser melting (SLM) technology. The microstructure and mechanical properties of the SLM-formed and heat-treated samples were studied in detail. The results indicated that an in-situ reaction occurred during the SLM process, producing acicular TiB, whisker TiB and granular TiC. The microhardness of the selective laser melted sample increased with increasing B4C content. When wt.% (B4C) is 0.05, the mechanical properties, i.e., compressive strength, compressive strain, tensile strength and elongation, of the SLM-formed sample are 2021 MPa, 29.98%, 1225 MPa and 14.17%, respectively. In addition, some of the SLM-formed samples were solution-treated at different temperatures (950 °C, 1000 °C, 1050 °C), and the microstructures were obviously changed, resulting in an increase in grain size and agglomeration of the in-situ reaction products. As the solution temperature increases, the microhardness of the composites decreases, and the tensile strength, compressive strength and strain tend to increase, but they are generally weaker than those of the original samples. When the solution temperature is 1050 °C, the tensile strength and elongation of the composite are 1402 MPa and 13.74%, respectively.

Keywords

• Titanium matrix composites
• Laser selective melting
• In-situ reaction
• Microstructure
• Mechanical properties