In Situ Observation of Phase Transformation of Powder Sintering from Ni/TiH_2 Using Neutron Diffraction

摘要

The utilisation of TiH_2 powder in titanium and its alloys sintering has been receiving increasing interest. This study presents an in situ observation of phase transformation in blended TiH_2 and Ni powders sintering using neutron diffraction. Densification and microstructure of the as-sintered NiTi alloy, and the hydrogen release during sintering is reported. The sintering mechanism involving the use of TiH_2 is discussed for synthesizing NiTi shape memory alloy. The sintered porous alloy has 26.9 % open porosity and exhibits volumetric shrinkage. The predominant phase identified in the produced NiTi alloys sintered at 1373 K is B2 NiTi phase with the presence of other minor phases.