Effects of temperature and heating rate on the mechanical properties of the tensile specimens of magnesium alloy AZ31 were experimentally investigated using a Gleeble-1500 thermo-mechanical material testing system.The...Effects of temperature and heating rate on the mechanical properties of the tensile specimens of magnesium alloy AZ31 were experimentally investigated using a Gleeble-1500 thermo-mechanical material testing system.The metallurgraphs of the fracture section of the specimens were also experimentally observed and analyzed for exploring their failure mechanism under different temperatures and heating rates.The results show that the higher the temperature,the lower the ultimate strength of the specimens.And the higher the heating rate,the higher the ultimate strength of the specimens.The high temperatures and high heating rates will induce microvoids in the specimens which make the specimens failure under relatively low loads.展开更多
The qualitative relationship between hydrogen concentration and notch tensile strength has been investigated for 5Ni-16Cr-Mo steel with different strength.The notch tensile strength was determined by means of slow str...The qualitative relationship between hydrogen concentration and notch tensile strength has been investigated for 5Ni-16Cr-Mo steel with different strength.The notch tensile strength was determined by means of slow strain rate test(SSRT)on circumferentially notched round bar specimens with the notch root radius of 0.15 mm after hydrogen charging.Meanwhile,the hydrogen diffusion behaviors of various strength steel were studied by thermal desorption spectroscopy(TDS)analysis.The SSRT results show that the T460 steel has higher susceptibility of hydrogen embrittlement in contrast with T520 steel.The activation energies and microstructure indicate that the dislocations and interfaces of martensitic laths are hydrogen traps in 5Ni-16Cr-Mo steel.By SSRT,the elastic limit of charged specimen loaded in air is higher than the flow stress without hydrogen charging before unloading,while the difference is defined as hydrogen-induced stress.The value of hydrogen-induced stress σ*increases linearly with hydrogen concentration:σ*=−0.622+2.015C0.The finite element analysis results of stress distributions near the notch tip have shown that the maximum principal stress increases with the notch root radius decreasing.展开更多
The response and failure of magnesium alloy AZ31 specimens subjected to different pre-loaded-stress levels and heating rates were investigated with a Gleeble-1500 thermo-mechanical material testing system.It is found ...The response and failure of magnesium alloy AZ31 specimens subjected to different pre-loaded-stress levels and heating rates were investigated with a Gleeble-1500 thermo-mechanical material testing system.It is found that the increases of either pre-loaded stresses or heating-rates decrease the failure temperatures of the specimens.The metallographs of the tested specimens were also observed.It is shown that the high heating-rate may cause stronger local thermal inconsistency,which remarkably increases the microdefects and reduces the macroscopic mechanical properties of the material.展开更多
基金Projects(10872221,50621403)supported by the National Natural Science Foundation of China
文摘Effects of temperature and heating rate on the mechanical properties of the tensile specimens of magnesium alloy AZ31 were experimentally investigated using a Gleeble-1500 thermo-mechanical material testing system.The metallurgraphs of the fracture section of the specimens were also experimentally observed and analyzed for exploring their failure mechanism under different temperatures and heating rates.The results show that the higher the temperature,the lower the ultimate strength of the specimens.And the higher the heating rate,the higher the ultimate strength of the specimens.The high temperatures and high heating rates will induce microvoids in the specimens which make the specimens failure under relatively low loads.
基金Project(3220024018)supported by the Fundamental Research Funds for the Luoyang Sunrui Special Equipment Co.,Ltd.,China。
文摘The qualitative relationship between hydrogen concentration and notch tensile strength has been investigated for 5Ni-16Cr-Mo steel with different strength.The notch tensile strength was determined by means of slow strain rate test(SSRT)on circumferentially notched round bar specimens with the notch root radius of 0.15 mm after hydrogen charging.Meanwhile,the hydrogen diffusion behaviors of various strength steel were studied by thermal desorption spectroscopy(TDS)analysis.The SSRT results show that the T460 steel has higher susceptibility of hydrogen embrittlement in contrast with T520 steel.The activation energies and microstructure indicate that the dislocations and interfaces of martensitic laths are hydrogen traps in 5Ni-16Cr-Mo steel.By SSRT,the elastic limit of charged specimen loaded in air is higher than the flow stress without hydrogen charging before unloading,while the difference is defined as hydrogen-induced stress.The value of hydrogen-induced stress σ*increases linearly with hydrogen concentration:σ*=−0.622+2.015C0.The finite element analysis results of stress distributions near the notch tip have shown that the maximum principal stress increases with the notch root radius decreasing.
基金Projects(10872221,50621403)supported by the National Natural Science Foundation of China
文摘The response and failure of magnesium alloy AZ31 specimens subjected to different pre-loaded-stress levels and heating rates were investigated with a Gleeble-1500 thermo-mechanical material testing system.It is found that the increases of either pre-loaded stresses or heating-rates decrease the failure temperatures of the specimens.The metallographs of the tested specimens were also observed.It is shown that the high heating-rate may cause stronger local thermal inconsistency,which remarkably increases the microdefects and reduces the macroscopic mechanical properties of the material.
