Stiffness constants, dislocation line energies, and tensions of Ni3Al and of the γ′-phases of NIMONIC 105 and of NIMONIC PE16

The adiabatic stiffness constants Cik of four nickel-base alloys are determined in the temperature range 90 to 360 K: stoichiometric Ni3Al, γ′-105, γ′-PE16, NIMONIC 105. γ′-105 and γ′-PE16 are the γ-phases in the commercial superalloys NIMONIC 105 and NIMONIC PE16, respectively. The intermetallic compounds Ni3Al, γ′-105, and γ′-PE16 have the Ll2-crystal structure. The stiffness Cik is derived from the velocities at which ultrasonic pulses propagate along 〈110〉 directions in single crystals. The room-temperature stiffnes of Ni3Al is in excellent agreement with that published by Kayser and Stassis. For all four alloys the dislocation line energies and tensions of edge and screw dislocations are calculated within the framework of anisotropic theory of elasticity.