As the operating temperature of disk service was elevated from 650 °C to 700 °C, the creep properties urged to be paid attention. To investigate the creep properties of spray-formed low solvus, high refractory (LSHR) superalloy at about 700 °C, creep tests were conducted under seven different stress ranging from 690 MPa to 897 MPa. By means of creep curves and fracture microstructure observation, the creep behaviors and fracture mechanisms of spray-formed LSHR were analyzed. Stress exponent of the alloy was comparable to other disk superalloys such as Waspaloy and Inconel 718. It was interesting to find a transition in the creep behavior in two stress regimes. The contribution of grain boundary sliding in the low stress regime was greater than that in the higher stress. Under higher stress microcracks initiated along the intragranular slip bands because of strain concentration. The spray-forming LSHR exhibited a good creep resistance at low stress compared with other two superalloys by using Larson–Miller parameter, which was consistent with the transition of fracture behaviors.

Hot compression tests of a hot isostatically pressed (HIPed) Ni based powder metallurgy (P/M) superalloy were carried out under various combinations of temperatures and strain rates. To bridge the relationship between stresses and strain rates, constitutive equations were established based on a hyperbolic sine Arrhenius equation, which yielded predicted stresses under the test conditions. It was found that the predict values fit the experimental values with good accuracy. Processing maps of the alloy under the test conditions were established; and the corresponding microstructures after test were examined to elaborate the workability of the alloy. It revealed that surface cracks occurred when strain was higher than 0.25, which initiated at the prior powder boundaries (PPBs) and propagated along the boundaries. The optimum hot working parameters for the alloy were proposed to beat the strain rate of 0.014 s−1 and 1075 °C.

The deformation behaviors (flow behavior, power dissipation, dynamic recrystallization, and microstructure evolution) of a typical powder metallurgy nickel-based superalloy were investigated in compression tests at temperatures range of 1020–1140 °C and strain rates range of 0.001–1.0 s−1 with the true strains of 0.3, 0.5, and 0.7, respectively. The efficiency of power dissipation can be shown by the power dissipation maps at different true strains. The results showed that true strain had a great effect on the power dissipation. Besides, the deformed microstructures were investigated. The processes of microstructure evolution at different deformation temperatures and strain rates are different. The continuous dynamic recrystallization takes place at the deformation condition of 1080 °C/0.1 s−1. The fine and uniform dynamic recrystallized grains gradually replace the pre-existing grains with the increase of true strain. The discontinuous dynamic recrystallization takes place at the deformation condition of 1110 °C/0.001 s−1. The fine dynamic recrystallized grains grow up and a part of new fine grains appear in the dynamic recrystallized grains because of the periodic dynamic recrystallization.