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e of TiH2 powder in titanium powder metallurgy (PM) has attracted much attention since the discovery that TiH2 may enhance powder densification.[1,2] As summarized by Robertson and Schaffer,[3] the enhanced densification involving the use of TiH2 powder may originate from (a) volumetric reduction during TiH2 decomposition, (b) generally finer original particle size and/or fragmentation during compaction, (c) generally lower oxygen content in hydride powder, and (d) most prominently cleansing effect and hence increased chemical activity of titanium surface caused by atomic hydrogen release. Many titanium alloys have been explored using TiH2 powder, including pure titanium, Ti-6Al-4V, Ti-5Al-2.5Fe, and intermetallic TiAl.[2–8] A more common use of TiH2 is to produce metallic foams, resulting from the gas bubbles entrapped in the viscous molten metals. A typical example is in producing aluminum metal foams where H2 gas bubbles are released from TiH2 in aluminum melt.[9,10] TiH2 powder is also used in producing NiTi shape memory alloy foams through a powder sintering route.[11–23] It is noted that a porous NiTi alloy can also be sintered from elemental Ti powder in place of TiH2; but the use of latter leads to a reduced pore size, increased pore number, more uniform pore size distribution, and increased degree of sintering.[13,15,16] Our previous works also confirm this finding.[21,22] However, it is debatable whether the increased sintering and reduced porosity is caused by dehydrogenation or by the use of finer TiH2 powder. In most cases,[13,15,16] Ti powder used is