The flow behavior of delta-processed Inconel 718 was studied in temperature range of 900-1 060℃ and strain rate range of 0.001-0.5s-1.The effects of friction and temperature on the compressive deformation behavior we...The flow behavior of delta-processed Inconel 718 was studied in temperature range of 900-1 060℃ and strain rate range of 0.001-0.5s-1.The effects of friction and temperature on the compressive deformation behavior were investigated,and the flow stress-strain error caused by friction was revised.The results showed that the effect of the friction was obvious with increasing strain rate and decreasing deformation temperature.The revised flow stress is decreased by increasing temperature and decreasing strain rate and exhibits a typical dynamic recrystallization behavior.The constitutive model has been developed through a hyperbolic-sine Arrhenius type equation to relate the flow stress,strain rate and temperature.The influence of strain has also been incorporated by considering the variation of material constants as a function of strain.The prediction accuracy of developed constitutive model has been assessed using standard statistical formulae.According to the analysis results,the proposed deformation constitutive equation gives an accurate and precise estimate of flow stress of delta-processed Inconel 718 alloy.展开更多
In order to optimize the deformation processing, the hot deformation behavior of Co-Cr-Mo-Cu （here- after named as Co-Cu） alloy was studied in this paper at a deformation temperature range of 950-1150 ℃ and a strai...In order to optimize the deformation processing, the hot deformation behavior of Co-Cr-Mo-Cu （here- after named as Co-Cu） alloy was studied in this paper at a deformation temperature range of 950-1150 ℃ and a strain rate range of 0.008-5 s^-1. Based on the true stress-true strain curves, a constitutive equation in hyperbolic sin function was established and a hot processing map was drawn. It was found that the flow stress of the Co-Cu alloy increased with the increase of the strain rate and decreased with the increase of the deforming temperature. The hot processing map indicated that there were two unstable regions and one well-processing region. The microstructure, the hardness distribution and the electro- chemical properties of the hot deformed sample were investigated in order to reveal the influence of the hot deformation. Microstructure observation indicated that the grain size increased with the increase of the deformation temperature but decreased with the increase of the strain rate. High temperature and low strain rate promoted the crystallization process but increased the grain size, which results in a reduction in the hardness. The hot deformation at high temperature （1100-1150 ℃） would reduce the corrosion resistance slightly. The final optimized deformation process was： a deformation temperature from 1050to 1100 ℃, and a strain rate from 0.008 to 0.2 s^-1, where a completely recrystallized and homogeneously distributed microstructure would be obtained.展开更多
基金Sponsored by National High Technology Research and Development Program of China(2012AA03A514)Youth Scientific Research Foundation of Central South University of Forestry and Technology of China(QJ2010001A)
文摘The flow behavior of delta-processed Inconel 718 was studied in temperature range of 900-1 060℃ and strain rate range of 0.001-0.5s-1.The effects of friction and temperature on the compressive deformation behavior were investigated,and the flow stress-strain error caused by friction was revised.The results showed that the effect of the friction was obvious with increasing strain rate and decreasing deformation temperature.The revised flow stress is decreased by increasing temperature and decreasing strain rate and exhibits a typical dynamic recrystallization behavior.The constitutive model has been developed through a hyperbolic-sine Arrhenius type equation to relate the flow stress,strain rate and temperature.The influence of strain has also been incorporated by considering the variation of material constants as a function of strain.The prediction accuracy of developed constitutive model has been assessed using standard statistical formulae.According to the analysis results,the proposed deformation constitutive equation gives an accurate and precise estimate of flow stress of delta-processed Inconel 718 alloy.
基金financially supported by the National Natural Science Foundation of China (Nos. 81071262, 31271024 and 31470930)the Funding from Northeastern University ("985 program", Nos. N141008001 and LZ2014018), China
文摘In order to optimize the deformation processing, the hot deformation behavior of Co-Cr-Mo-Cu （here- after named as Co-Cu） alloy was studied in this paper at a deformation temperature range of 950-1150 ℃ and a strain rate range of 0.008-5 s^-1. Based on the true stress-true strain curves, a constitutive equation in hyperbolic sin function was established and a hot processing map was drawn. It was found that the flow stress of the Co-Cu alloy increased with the increase of the strain rate and decreased with the increase of the deforming temperature. The hot processing map indicated that there were two unstable regions and one well-processing region. The microstructure, the hardness distribution and the electro- chemical properties of the hot deformed sample were investigated in order to reveal the influence of the hot deformation. Microstructure observation indicated that the grain size increased with the increase of the deformation temperature but decreased with the increase of the strain rate. High temperature and low strain rate promoted the crystallization process but increased the grain size, which results in a reduction in the hardness. The hot deformation at high temperature （1100-1150 ℃） would reduce the corrosion resistance slightly. The final optimized deformation process was： a deformation temperature from 1050to 1100 ℃, and a strain rate from 0.008 to 0.2 s^-1, where a completely recrystallized and homogeneously distributed microstructure would be obtained.
