Manufacturing process and mechanical properties of fine TiB dispersed Ti–6Al–4V alloy composites obtained by reaction sintering

Abstract

Fine TiB dispersed Ti–6Al–4V alloy composites were developed using a powder metallurgy method, in which high hardness, high strength, high wear resistance and superplasticity were expected. Boride powder (i.e. TiB 2), MoB, CrB and Ti–6Al–4V prealloyed powder were mechanically blended in a high energy ball mill. The powder obtained was pressed into dies and consolidated by reaction sintering. The dispersed boride particles produced reactive TiB in the matrix during sintering. In the hot isostatic press (HIP) which followed, samples showed a very fine microstructure of TiB dispersing homogeneously. At room temperature, hardness, compressive strength and wear resistance had the tendency to increase as blended boride content increases. The results of compressive and tensile test at 1173 K, in the strain rate range of 1×10 −3–1×10 −4 s −1, showed that TiB dispersed composites exhibited m values of no less than 0.38 and large elongation and superplasticity was confirmed.