7075 aluminum alloy was used to obtain elbow parts by complex thixoextrusion and the microstructure evolution and mechanical properties during this process were studied by SEM,TEM and other analytical methods.The resu...7075 aluminum alloy was used to obtain elbow parts by complex thixoextrusion and the microstructure evolution and mechanical properties during this process were studied by SEM,TEM and other analytical methods.The results show that different parts in 7075 aluminum alloy show quite different microstructures.The microstructure of the thin walls formed by back-extrusion is stratified,and the bottom of the parts formed by angular extrusion is obviously deformed.Shear forces contribute to the crushing of grains and the coarse second phase.The main strengthening phases in the material areηphase and E phase,whose amounts greatly decrease during heating to semi-solid and thixoextrusion.After heat treatment,they can precipitate evenly to improve the mechanical properties of the material.The average tensile strength of whole part after thixoextrusion and heat treatment is 485.49 MPa,while the average elongation is 5.49%.展开更多
In order to evaluate the impact of green production introduced by the manufacturer and study the competitive strategy between two retailers,four strategic models among diverse retailers,i.e.,Cournot,Stackelberg and tw...In order to evaluate the impact of green production introduced by the manufacturer and study the competitive strategy between two retailers,four strategic models among diverse retailers,i.e.,Cournot,Stackelberg and two cases of collusion,are constructed.The optimal decision is obtained by the game theory and numerical analysis.The results indicate that the manufacturer's marginal profitability is no less than that of the two retailers.However,due to the manufacturer's green cost,the downstream profitability of the supply chain may exceed the upstream manufacturer's profitability.The retailers'Cournot behavior causes the manufacturer to acquire the highest profitability and set the highest green level.However,there is an opposite result in collusion.Two retailers will choose Cournot pricing when the consumer's green sensitivity is higher than a threshold.When consumers are more sensitive to the price difference of products,retailers prefer collusion,and then choose the Stackelberg behavior.Manufacturers'profitability will increase as competition among retailers intensifies.Proper competition allows two duopolistic retailers to acquire a higher profitability.展开更多
文摘7075 aluminum alloy was used to obtain elbow parts by complex thixoextrusion and the microstructure evolution and mechanical properties during this process were studied by SEM,TEM and other analytical methods.The results show that different parts in 7075 aluminum alloy show quite different microstructures.The microstructure of the thin walls formed by back-extrusion is stratified,and the bottom of the parts formed by angular extrusion is obviously deformed.Shear forces contribute to the crushing of grains and the coarse second phase.The main strengthening phases in the material areηphase and E phase,whose amounts greatly decrease during heating to semi-solid and thixoextrusion.After heat treatment,they can precipitate evenly to improve the mechanical properties of the material.The average tensile strength of whole part after thixoextrusion and heat treatment is 485.49 MPa,while the average elongation is 5.49%.
基金The National Natural Science Foundation of China(No.51875332)the Capacity Building Projects of Some Local Universities of Shanghai Science and Technology Commission(No.18040501600).
文摘In order to evaluate the impact of green production introduced by the manufacturer and study the competitive strategy between two retailers,four strategic models among diverse retailers,i.e.,Cournot,Stackelberg and two cases of collusion,are constructed.The optimal decision is obtained by the game theory and numerical analysis.The results indicate that the manufacturer's marginal profitability is no less than that of the two retailers.However,due to the manufacturer's green cost,the downstream profitability of the supply chain may exceed the upstream manufacturer's profitability.The retailers'Cournot behavior causes the manufacturer to acquire the highest profitability and set the highest green level.However,there is an opposite result in collusion.Two retailers will choose Cournot pricing when the consumer's green sensitivity is higher than a threshold.When consumers are more sensitive to the price difference of products,retailers prefer collusion,and then choose the Stackelberg behavior.Manufacturers'profitability will increase as competition among retailers intensifies.Proper competition allows two duopolistic retailers to acquire a higher profitability.
