In order to investigate the hot deformation behavior of superalloy GH696, isothermal compression experiments were carried out at deformation temperatures of 880?1120 °C and strain rates of 0.01?10 s?1. And the de...In order to investigate the hot deformation behavior of superalloy GH696, isothermal compression experiments were carried out at deformation temperatures of 880?1120 °C and strain rates of 0.01?10 s?1. And the deformation amount of all the samples was 50%. The strain rate sensitivity exponent (m) and strain hardening exponent (n) under different deformation conditions were calculated, meanwhile the effects of the processing parameters on the values ofm andn were analyzed. The results show that the flow stress increases with the increase of strain rate and the decrease of deformation temperature. The value ofm increases with the increase of deformation temperature and decreases with the increase of strain rate, while the value ofn decreases with the increase of deformation temperature. A novel flow stress model during hot deformation of superalloy GH696 was also established. And the calculated flow stress of the alloy is in good agreement with the experimental one.展开更多
High entropy alloys(HEAs)have attracted extensive attention due to their excellent properties in harsh environments.Here,we introduced the HEA NbMoTaW into the laminated structure to synthesize the Cu/HEA nanolaminate...High entropy alloys(HEAs)have attracted extensive attention due to their excellent properties in harsh environments.Here,we introduced the HEA NbMoTaW into the laminated structure to synthesize the Cu/HEA nanolaminates(NLs)with equal layer thickness h spanning from 5 to 100 nm,and comparatively investigated the size dependent mechanical properties and plastic deformation.The experimental results demonstrated that the hardness of Cu/HEA NLs increased with decreasing h,and reached a plateau at h≤50 nm,while the strain rate sensitivity m unexpectedly went through a maximum with reducing h.The emergence of maximum m results from a transition from the synergetic effect of crystalline constituents to the competitive effect between crystalline Cu and amorphous-like NbMoTaW.Microstructural examinations revealed that shear banding caused by the incoherent Cu/HEA interfaces occurred under severe deformation,and the soft Cu layers dominated plastic deformation of Cu/HEA NLs with large h.展开更多
文摘In order to investigate the hot deformation behavior of superalloy GH696, isothermal compression experiments were carried out at deformation temperatures of 880?1120 °C and strain rates of 0.01?10 s?1. And the deformation amount of all the samples was 50%. The strain rate sensitivity exponent (m) and strain hardening exponent (n) under different deformation conditions were calculated, meanwhile the effects of the processing parameters on the values ofm andn were analyzed. The results show that the flow stress increases with the increase of strain rate and the decrease of deformation temperature. The value ofm increases with the increase of deformation temperature and decreases with the increase of strain rate, while the value ofn decreases with the increase of deformation temperature. A novel flow stress model during hot deformation of superalloy GH696 was also established. And the calculated flow stress of the alloy is in good agreement with the experimental one.
基金supported by the National Natural Science Foundation of China (51621063, 51722104, 51625103, 51790482, 51761135031 and 51571157)the National Key Research and Development Program of China (2017YFA0700701 and 2017YFB0702301)+6 种基金the 111 Project 2.0 of China (BP2018008)the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologiesthe Fundamental Research Funds for the Central Universities (xzy022019071)the Fok Ying-Tong Education Foundation (161096)China Postdoctoral Science Foundation (2017T100744)Shaanxi Province innovative talents promotion Projects (2018KJXX-004)the support from China Postdoctoral Science Foundation (2016M602811)
文摘High entropy alloys(HEAs)have attracted extensive attention due to their excellent properties in harsh environments.Here,we introduced the HEA NbMoTaW into the laminated structure to synthesize the Cu/HEA nanolaminates(NLs)with equal layer thickness h spanning from 5 to 100 nm,and comparatively investigated the size dependent mechanical properties and plastic deformation.The experimental results demonstrated that the hardness of Cu/HEA NLs increased with decreasing h,and reached a plateau at h≤50 nm,while the strain rate sensitivity m unexpectedly went through a maximum with reducing h.The emergence of maximum m results from a transition from the synergetic effect of crystalline constituents to the competitive effect between crystalline Cu and amorphous-like NbMoTaW.Microstructural examinations revealed that shear banding caused by the incoherent Cu/HEA interfaces occurred under severe deformation,and the soft Cu layers dominated plastic deformation of Cu/HEA NLs with large h.
