Formation and effect of intermetallic compounds in the vacuum arc melting of titanium/copper alloy

Abstract

The effect of Ti element content on the precipitation of intermetallic compounds, microstructure and mechanical properties of Ti–Cu alloy samples during vacuum arc melting was studied. The results showed that when the TC4:Cu mass ratio were 1:20, 1:10, and 3:20, the tensile strength of the sample were 638 MPa, 945.5 MPa, 914.9 MPa, the elongation were 21.1 %, 3.5 %, 0.9 %, and the microhardness were Hv 195.6, Hv 259.01, Hv 275.6, respectively. The solidification behavior of the melt pool and the precipitation behavior of IMCs were also studied. When the Ti content exceeds the solid solubility of titanium in copper, dendrite segregation will occur during the solidification process, resulting in the precipitation of a large number of IMCs. The IMCs precipitated in Ti–Cu melting samples include TiCu, Ti3Cu4, TiCu3, and TiCu4. Among them, TiCu4 is precipitated from the solid solution due to the decrease in melt temperature in the later stage of solidification, while TiCu, Ti3Cu4, and TiCu3 are produced by liquid-phase precipitation or transformation reaction of the TiCu phase. TiCu and Ti3Cu4 are the main causes of alloy fracture.