Hot processing maps and microstructure evolution of GH4698 alloy
The hot deformation behaviors of GH4698 superalloy were studied.The microstructure evolution laws and hot working perform-ance were analyzed under the conditions with deformation temperature of 960～1160 ℃,and strain rate of 0.001～10 s-1.The dynamic recrystallization(DRX)diagrams of GH4698 alloy were constructed to analyze the microstructure evolution mechanism.In addition,the average grain size diagrams of DRX grains were constructed to analyze the infulence of DRX on microstructure,the 3D instability diagram and 3D power dissipation diagram were constructed to evaluate the hot working performance,and the optimum hot working interval was ob-tained.According to the DRX degree and the average grain size of DRX,the hot working interval was further optimized and the optimized deformation temperature is 1017-1065 ℃,the strain rate is 0.001-0.005 s-1,and the deformation temperature is 1087-1160 ℃,the strain rate is 0.017-0.115 s-1.At the same time,the microstructure of the material was characterized using electron backscattered dif-fraction(EBSD)technology.The results show that the microstructure of the material is sensitive to strain rate,and the volume fraction of DRX is inversely proportional to strain rate.Continuous dynamic recrystallization(DDRX)is the main deformation mechanism of GH4698 alloy.It is mainly show that DDRX predominating at low strain rates,CDRX predominating at medium strain rates,and CDRX+DDRX predominating at high strain rates;the mechanism of DRX is CDRX+DDRX at low temperatures,while the main DRX mechanism is DDRX at high temperatures.
万方数据
维普
