PHASE-EQUILIBRIA IN THE GAMMA'-RICH REGION OF THE NI-AL-HF SYSTEM

In the present study the constitution diagram of the gamma'-rich regio n of the Ni-Al-Hf system at 1403 K was investigated. Depending on the composition of the alloy, various phases such as gamma', beta, gamma, gamma(1) and eta(1) were identified. Three tie lines between gamma' an d beta, three tie lines between gamma' and gamma, one tie line between gamma' and eta(1) and one tie triangle between gamma', gamma and gamm a(1) were established. One four-phase equilibrium between gamma', gamm a, gamma(1) and eta(1) was also identified. These results accurately e stablished the phase boundary of gamma' phase.