To quickly predict the fatigue limit of 6061 aluminum alloy,two assessment methods based on the temperature evolution and the steady ratcheting strain difference under cyclic loading,respectively,were proposed.The tem...To quickly predict the fatigue limit of 6061 aluminum alloy,two assessment methods based on the temperature evolution and the steady ratcheting strain difference under cyclic loading,respectively,were proposed.The temperature evolutions during static and cyclic loadings were both measured by infrared thermography.Fatigue tests show that the temperature evolution was closely related to the cyclic loading,and the cyclic loading range can be divided into three sections according to the regular of temperature evolution in different section.The mechanism of temperature evolution under different cyclic loadings was also analyzed due to the thermoelastic,viscous,and thermoplastic effects.Additionally,ratcheting strain under cyclic loading was also measured,and the results show that the evolution of the ratcheting strain under cyclic loading above the fatigue limit undergone three stages:the first increasing stage,the second steady state,and the final abrupt increase stage.The fatigue limit of the 6061 aluminum alloy was quickly estimated based on transition point of linear fitting of temperature increase and the steady value of ratcheting strain difference.Besides,it is feasible and quick of the two methods by the proof of the traditional S-N curve.展开更多
With visible light(λ=450 nm) irradiation of a catalytic amount of platinum(Ⅱ) terpyridyl complex, 1,3,5-triaryl-2-pyrazolines can be smoothly converted to their corresponding pyrazoles and hydrogen in quantitative y...With visible light(λ=450 nm) irradiation of a catalytic amount of platinum(Ⅱ) terpyridyl complex, 1,3,5-triaryl-2-pyrazolines can be smoothly converted to their corresponding pyrazoles and hydrogen in quantitative yields with no use of any oxidant at room temperature.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51505322 and 51775366)the Natural Science Foundation of Shanxi Province,China(No.201801D221137).
文摘To quickly predict the fatigue limit of 6061 aluminum alloy,two assessment methods based on the temperature evolution and the steady ratcheting strain difference under cyclic loading,respectively,were proposed.The temperature evolutions during static and cyclic loadings were both measured by infrared thermography.Fatigue tests show that the temperature evolution was closely related to the cyclic loading,and the cyclic loading range can be divided into three sections according to the regular of temperature evolution in different section.The mechanism of temperature evolution under different cyclic loadings was also analyzed due to the thermoelastic,viscous,and thermoplastic effects.Additionally,ratcheting strain under cyclic loading was also measured,and the results show that the evolution of the ratcheting strain under cyclic loading above the fatigue limit undergone three stages:the first increasing stage,the second steady state,and the final abrupt increase stage.The fatigue limit of the 6061 aluminum alloy was quickly estimated based on transition point of linear fitting of temperature increase and the steady value of ratcheting strain difference.Besides,it is feasible and quick of the two methods by the proof of the traditional S-N curve.
基金supported by the National Basic Research Program of China(2013CB8345052013CB834804)+3 种基金the National Natural Science Foundation of China(213904049142730321402217)the Key Research Programme of the Chinese Academy of Sciences(KGZD-EW-T05)
文摘With visible light(λ=450 nm) irradiation of a catalytic amount of platinum(Ⅱ) terpyridyl complex, 1,3,5-triaryl-2-pyrazolines can be smoothly converted to their corresponding pyrazoles and hydrogen in quantitative yields with no use of any oxidant at room temperature.