MECHANICAL STRENGTH OF THE BINARY COMPOUND NI3AL

The mechanical properties of binary Ni76.6Al23.4 single crystalline sp ecimens have been studied in compression tests over a wide range of te mperatures (293-1100 K). The resolved proof stress (tau(0.2%)) and the corresponding work-hardening rate (theta(0.2%)) have been measured as a function of temperature. A technique of repeated stress relaxations has been used to investigate the variation in the density of mobile d islocations that occurs during such transient tests. These experiments have been complemented with strain-rate changes for characterising th e strain-rate sensitivity of the flow stress. The high hardening rates and their variation with temperature seem to correlate well with the values of the mobile dislocation exhaustion rates. The strain rate sen sitivity of the stress exhibits negative values between 293 and 600 K, below the stress anomaly domain. These mechanical parameters are disc ussed in terms of the available dislocation mechanisms. (C) 1997 Elsev ier Science S.A.