Fabrication and Microstructural Analysis of Boride/Ti-6A1-4V Surface-Alloyed Materials Using High- Energy Electron Beam Irradiation

摘要

The present study is concerned with fabricationand microstructural analysis of boride/I'i-6Al-4V surface-alloyed materials using irradiation of high-energy electronbeam. Mixtures of TiB_2 or MoB boride powders and CaF_2flux were placed on a Ti-6Al-4V alloy substrate, and thenelectron beam was irradiated on these mixtures using anelectron beam accelerator. In the specimens processed with aflux mixing ratio of 40 wt. percent, the melted region of l.l~l.5mm in thickness was homogeneously formed without defects,and contained a large amount of TiB borides. Thismicrostructural modification including the formation of TiBborides and #beta#-Ti matrix in the surface-alloyed layersgreatly improved hardness, about twice higher than hardness ofthe Ti alloy substrate. These findings suggested that thesurface-alloying using high-energy electron beam irradiationwas economical and useful for the development of titanium-base surface-alloyed materials with improved hardness.