THE EFFECT OF TRAPPED HYDROGEN ON MECHANICAL BEHAVIOR OF Ni_3(Si,Ti) INTERMETALLIC COMPOUND

摘要

The effect of residual hydrogen on mechanical properties and fracture behavior of Ni_3(Si,Ti) single crystals and polycrystals is investigated by tensile tests, using materials with a low level (< 0.5 mass ppm) and high level ( ～ 2 mass ppm) hydrogen content, and also with and without a trace amount of boron (50 ppm). Furthermore, the effect of pre-plastic deformation on these phenomena is investigated. Tensile elongation and fracture mode of the Ni_3(Si,Ti) single crystals are primarily insensitive to the hydrogen content. The tensile elongation of the Ni_3(Si,Ti) polycrystals are markedly reduced by a high level of hydrogen content, and associated fractography shows a mainly brittle intergranular fracture pattern.