Submerged friction stir processing(SFSP)with flowing water was employed to alleviate the porosities and coarse-grained structure introduced by wire-arc manufacturing.As a result,uniform and ultrafine grained(UFG)struc...Submerged friction stir processing(SFSP)with flowing water was employed to alleviate the porosities and coarse-grained structure introduced by wire-arc manufacturing.As a result,uniform and ultrafine grained(UFG)structure with average grain size of 0.83μm was achieved with the help of sharply reduced heat input and holding time at elevated temperature.The optimized UFG structure enabled a superior combination of strength and ductility with high ultimate tensile strength and elongation of 273.17 MPa and 15.39%.Specifically,grain refinement strengthening and decentralized θ(Al_(2)Cu)phase in the sample subjected to SFSP made great contributions to the enhanced strength.In addition,the decrease in residual stresses and removal of pores substantially enhance the ductility.High rates of cooling and low temperature cycling,which are facilitated by the water-cooling environment throughout the machining process,are vital in obtaining superior microstructures.This work provides a new method for developing a uniform and UFG structure with excellent mechanical properties.展开更多
Dear Editor,Myocardial infarction(MI)is characterized by the loss of functional cardiomyocyte(CM)in the heart,resulting in cardiac systolic dysfunction and heart failure.1,2 Increasing evidence suggested that in the h...Dear Editor,Myocardial infarction(MI)is characterized by the loss of functional cardiomyocyte(CM)in the heart,resulting in cardiac systolic dysfunction and heart failure.1,2 Increasing evidence suggested that in the heart of neonatal mice after apical resection(AR),the CM can proliferate and regenerate myocardium to repair the heart.While in the heart of adult mice after MI,the CM loses the ability to re-enter the cell cycle but undergoes hypertrophic growth.展开更多
文摘Submerged friction stir processing(SFSP)with flowing water was employed to alleviate the porosities and coarse-grained structure introduced by wire-arc manufacturing.As a result,uniform and ultrafine grained(UFG)structure with average grain size of 0.83μm was achieved with the help of sharply reduced heat input and holding time at elevated temperature.The optimized UFG structure enabled a superior combination of strength and ductility with high ultimate tensile strength and elongation of 273.17 MPa and 15.39%.Specifically,grain refinement strengthening and decentralized θ(Al_(2)Cu)phase in the sample subjected to SFSP made great contributions to the enhanced strength.In addition,the decrease in residual stresses and removal of pores substantially enhance the ductility.High rates of cooling and low temperature cycling,which are facilitated by the water-cooling environment throughout the machining process,are vital in obtaining superior microstructures.This work provides a new method for developing a uniform and UFG structure with excellent mechanical properties.
基金This work was supported by the National Nature Science Foundation of China[92168119/81872857/82100300]Heilongjiang Touyan Innovation Team Program[B.Z.C.],and HMU Marshal Initiative Funding(HMUMIF-21018).
文摘Dear Editor,Myocardial infarction(MI)is characterized by the loss of functional cardiomyocyte(CM)in the heart,resulting in cardiac systolic dysfunction and heart failure.1,2 Increasing evidence suggested that in the heart of neonatal mice after apical resection(AR),the CM can proliferate and regenerate myocardium to repair the heart.While in the heart of adult mice after MI,the CM loses the ability to re-enter the cell cycle but undergoes hypertrophic growth.
