水素中時効による Cu-Ti 希薄合金中のチタン水素化物の生成とその電気的・力学的特性への影響

抄録

  We have investigated the specific contributions of titanium-hydride precipitates to the improvement of electrical conductivity and strength for Cu-0.36 mol% Ti alloys aged in a hydrogen atmosphere at 773 K, where Cu₄Ti phase is not to appear. During the aging, titanium-hydride particles, which have a composition of H/Ti=2, are formed by reaction of solute titanium with hydrogen diffused into the alloy. The particles have an octahedral shape with facets parallel to {111} of the matrix. The size and volume fraction of the hydride particles increase with aging time, and then level off after aging for 100 h, while the number density exhibits a maximum at 24 h. The precipitation reduces the concentration of solute titanium in the matrix and leads to significant improvement of the electrical conductivity, to the level comparable to pure copper. The dispersed TiH₂ particles gives rise to strengthening with the Orowan mechanism, of approximately 40 MPa at a maximum in yield strength.