Hot deformation behavior and microstructure evolution of NiAl-9HfO2 composite

The hot deformation behavior and microstructure evolution of the new NiAl-9%HfO2 composite synthesized by hot pressing sintering were researched by hot compression tests at temperatures of 1250-1400 degrees C and strain rates of 10(-3)-10(-1) s(-1) under a true strain of 0.693. The Arrhenius constitutive model was established on account of the stress-strain curves corrected by friction and adiabatic. The processing maps were also developed and the features of microstructure inferred by the processing map were corresponded to the microstructure observation. The optimum hot deformation processing window was 1300-1350 degrees C/0.03-0.01 s(-1). In addition, the microstructure evolution and the softening mechanism during hot deformation were discussed in detail. Based on the room-temperature compression test, the samples deformed at 1350 degrees C with a strain rate of 0.03 s(-1) exhibited the highest performance with the yield strength and ultimate compression deformation increasing by 22.6% and 52.2% compared with the original samples, respectively. This work provided more theoretical guidance for the hot processing of NiAl-based composites and further promoted their application.

Automated summary

The hot deformation behavior and microstructure evolution of the new NiAl-9%HfO2 composite were studied through hot compression tests, leading to the establishment of an Arrhenius constitutive model and development of processing maps. The optimal hot deformation processing window was identified, and detailed discussions on microstructure evolution and softening mechanism were conducted. The study also found that samples deformed at 1350 degrees C with a strain rate of 0.03 s(-1) exhibited the highest performance, indicating improvements in yield strength and ultimate compression deformation compared to the original samples.