Effect of Decrease of Hydride‐Induced Embrittlement in Nanocrystalline Titanium

Abstract

AbstractThe room‐temperature impact toughness, strength and ductility of nanocrystalline (NC) and microcrystalline (MC) titanium with hydrogen content ranging from 0.1 to 16 at.‐% (0.002 to 0.450 wt.‐%) are studied. NC titanium has higher strength and lower sensitivity to hydride‐induced brittle fracture than the MC material. In contrast to MC titanium, the elongation and impact toughness in the NC material does not decrease dramatically with increasing hydrogen content. Moreover, the fracture toughness in hydrogenated NC condition is found to be higher than that in MC titanium. This unusual result may be associated with the precipitation of equiaxial nanoscale hydrides in the interior of α‐grains in the NC material, while platelet hydrides are formed in MC titanium. One can expect that the risk of hydride‐induced embrittlement is lower in NC than in MC titanium, making the NC material attractive for potential application under conditions that may cause hydrogen saturation above the permissible level for MC titanium.