To achieve simultaneous improvement in wear resistance and corrosion resistance,we propose a novel strategy to successfully develop Mg matrix composites containing blocky primary Mg_(2)Si with small size instead of un...To achieve simultaneous improvement in wear resistance and corrosion resistance,we propose a novel strategy to successfully develop Mg matrix composites containing blocky primary Mg_(2)Si with small size instead of undesirable dendrite shape and large size.The tribological and corrosion behavior of Mg_(2)Si/AZ91 unmodified and modified with 2.0wt.%Sb was subsequently and systematically investigated.The results show that Sb addition can significantly modify the morphology of primary Mg_(2)Si to blocky polygon with smaller size of 12-25μm,but has less effect onα-Mg grain size.Compared with unmodified composite,Sb modified Mg_(2)Si/AZ91 composite has higher Brinell hardness and nearly unchanged microhardness of the matrix.Sb modified composite exhibits a 26%lower wear loss than unmodified composite suggesting the greatly improved wear resistance.Microstructure analyses indicate that the main wear mechanism of composites is dominated by abrasive wear,and Sb addition can decrease the width and depth of grooves,resulting in a weakened abrasive wear behavior.Additionally microcracks initiation on Sb modified Mg_(2)Si particles can be restricted during the sliding friction process because of higher toughness and blocky polygonal shape induced by Sb doping,which is responsible for the improved wear resistance.Interestingly,Sb modified Mg_(2)Si/AZ91composite also demonstrates a superior corrosion resistance than unmodified composite due to the decrease of calculated corrosion rate from1.57 mm/y to 0.74 mm/y,reduced by 52.8%.Such improvement is closely related to the reduced susceptibility to micro-galvanic corrosion,which is attributed to the reduced volta potential difference of Mg_(2)Si relative to the Mg matrix,from 365 mV to 210 mV.展开更多
The refining effect and mechanism of Sb on Mg2Si and the microstructure of the matrix were investigated.The results indicate that there are Mg3Sb2 particles in the composites with the addition of Sb,and Mg3Sb2 can pro...The refining effect and mechanism of Sb on Mg2Si and the microstructure of the matrix were investigated.The results indicate that there are Mg3Sb2 particles in the composites with the addition of Sb,and Mg3Sb2 can promote the formation of fine polygonal type Mg2Si by providing nucleation site.Meanwhile,the grain size of Sb modified alloy is finer than that of the matrix. The improved microstructure results in the improvement of mechanical properties.The ultimate tensile strength is increased by 12.2%with the addition of 0.8%Sb.展开更多
基金Natural Science Basic Research Program of Shaanxi(2022JQ-331)Fundamental Research Funds for the Central Universities(xjh03202101503)+1 种基金China Postdoctoral Science Foundation(2021M692518)National Key Research and Development Program of China(2021YFB3701204)。
文摘To achieve simultaneous improvement in wear resistance and corrosion resistance,we propose a novel strategy to successfully develop Mg matrix composites containing blocky primary Mg_(2)Si with small size instead of undesirable dendrite shape and large size.The tribological and corrosion behavior of Mg_(2)Si/AZ91 unmodified and modified with 2.0wt.%Sb was subsequently and systematically investigated.The results show that Sb addition can significantly modify the morphology of primary Mg_(2)Si to blocky polygon with smaller size of 12-25μm,but has less effect onα-Mg grain size.Compared with unmodified composite,Sb modified Mg_(2)Si/AZ91 composite has higher Brinell hardness and nearly unchanged microhardness of the matrix.Sb modified composite exhibits a 26%lower wear loss than unmodified composite suggesting the greatly improved wear resistance.Microstructure analyses indicate that the main wear mechanism of composites is dominated by abrasive wear,and Sb addition can decrease the width and depth of grooves,resulting in a weakened abrasive wear behavior.Additionally microcracks initiation on Sb modified Mg_(2)Si particles can be restricted during the sliding friction process because of higher toughness and blocky polygonal shape induced by Sb doping,which is responsible for the improved wear resistance.Interestingly,Sb modified Mg_(2)Si/AZ91composite also demonstrates a superior corrosion resistance than unmodified composite due to the decrease of calculated corrosion rate from1.57 mm/y to 0.74 mm/y,reduced by 52.8%.Such improvement is closely related to the reduced susceptibility to micro-galvanic corrosion,which is attributed to the reduced volta potential difference of Mg_(2)Si relative to the Mg matrix,from 365 mV to 210 mV.
基金Project（50765005）supported by the National Natural Science Foundation of China
文摘The refining effect and mechanism of Sb on Mg2Si and the microstructure of the matrix were investigated.The results indicate that there are Mg3Sb2 particles in the composites with the addition of Sb,and Mg3Sb2 can promote the formation of fine polygonal type Mg2Si by providing nucleation site.Meanwhile,the grain size of Sb modified alloy is finer than that of the matrix. The improved microstructure results in the improvement of mechanical properties.The ultimate tensile strength is increased by 12.2%with the addition of 0.8%Sb.
