Microstructure and mechanical properties of <i>in -situ</i> TiB reinforced Ti-based composite coating by induction cladding

Abstract

Induction cladding TiB/Ti composite coating was in-situ synthesized by induction heating the preplaced powder mixture of 90% Ti (atom fraction, the same below) and 10% boron on a Ti6Al4V substrate. The microstructure, phase composition and micro/nano mechanical properties of the coating were studied by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), microhardness tester and nanoindentation tester. The results indicate that the composite coating has a smooth surface and a dense microstructure without cracks and pores. A strong metallurgical adherence is formed between the coating and the substrate. During induction cladding process, B and Ti are fully reacted to in-situ form TiB reinforcements. The matrix of the coating consists of α-Ti phase and a few β-Ti phases. The reinforcements of in-situ synthesized TiB are uniformly distributed in the coating with a volume fraction about of 9.4%. Indentation hardness and modulus of the in-situ TiB particles are about 35 GPa and 545 GPa, respectively, which cause the increase of the microhardness of the composite coating to about 525HV0.2. It is increased by 67% as against the Ti6Al4V substrate.

Keywords

• induction cladding
• tib
• <i>in-situ</i> synthesis
• ti matrix composite coating
• mechanical property