The microstructures, tensile properties and compressive creep behaviors of Mg-5%Sn-（0-1.0）%Pb （mass fraction） alloys were studied. The microstructures of the Mg-Sn-Pb alloys consist of dendritic a-Mg and Mg2Sn pha...The microstructures, tensile properties and compressive creep behaviors of Mg-5%Sn-（0-1.0）%Pb （mass fraction） alloys were studied. The microstructures of the Mg-Sn-Pb alloys consist of dendritic a-Mg and Mg2Sn phase. The addition of Pb can refine the size of Mg2Sn phase and grain size, reduce the amount of Mg2Sn phase at grain or inter-dendrite boundaries and change the distribution of Mg2Sn phase. Pb exists in the Mg2Sn phase or dissolves in a-Mg matrix. The mechanical properties of the tested alloys at room temperature are improved with the addition of Pb. When the Pb content is over 0.5%, the mechanical properties are decreased gradually. The Mg-5%Sn-0.5%Pb shows the best ultimate tensile strength and elongation, 174 MPa and 14.3%, respectively. However, the compressive creep resistance of the Mg-Sn-Pb alloys is much lower than that of the Mg-Sn binary alloy at 175℃ with applied load of 55 MPa, which means that Pb has negative effects on the compressive creep resistance of the as-cast Mg-Sn alloys.展开更多
Similar friction welded joints of AA-7005 aluminum rods were fabricated using different combinations of process parameters such as friction pressure(1.0, 1.5 and 2.0 MPa) and friction time(10, 15 and 20 s). Interfacia...Similar friction welded joints of AA-7005 aluminum rods were fabricated using different combinations of process parameters such as friction pressure(1.0, 1.5 and 2.0 MPa) and friction time(10, 15 and 20 s). Interfacial microstructure and formation of intermetallic compounds at the joint interface were evaluated via scanning electron microscopy(SEM) equipped with energy dispersive spectrum(EDS), and optical microscopy(OM). Microstructural observations reveal the formation of intermetallic phases during the welding process which cannot be extruded from the interface. Theses phases influence the tensile strength of the resultant joints. From the tensile characteristics viewpoint, the greatest tensile strength value of 365 MPa is obtained at 1.5 MPa and 15 s. Finally, the role of microstructural features on tensile strength of resultant joints is discussed.展开更多
基金Project(03GG009-007-4) supported by the Key Program of Science and Technology Bureau of Sichuan Province, China
文摘The microstructures, tensile properties and compressive creep behaviors of Mg-5%Sn-（0-1.0）%Pb （mass fraction） alloys were studied. The microstructures of the Mg-Sn-Pb alloys consist of dendritic a-Mg and Mg2Sn phase. The addition of Pb can refine the size of Mg2Sn phase and grain size, reduce the amount of Mg2Sn phase at grain or inter-dendrite boundaries and change the distribution of Mg2Sn phase. Pb exists in the Mg2Sn phase or dissolves in a-Mg matrix. The mechanical properties of the tested alloys at room temperature are improved with the addition of Pb. When the Pb content is over 0.5%, the mechanical properties are decreased gradually. The Mg-5%Sn-0.5%Pb shows the best ultimate tensile strength and elongation, 174 MPa and 14.3%, respectively. However, the compressive creep resistance of the Mg-Sn-Pb alloys is much lower than that of the Mg-Sn binary alloy at 175℃ with applied load of 55 MPa, which means that Pb has negative effects on the compressive creep resistance of the as-cast Mg-Sn alloys.
文摘Similar friction welded joints of AA-7005 aluminum rods were fabricated using different combinations of process parameters such as friction pressure(1.0, 1.5 and 2.0 MPa) and friction time(10, 15 and 20 s). Interfacial microstructure and formation of intermetallic compounds at the joint interface were evaluated via scanning electron microscopy(SEM) equipped with energy dispersive spectrum(EDS), and optical microscopy(OM). Microstructural observations reveal the formation of intermetallic phases during the welding process which cannot be extruded from the interface. Theses phases influence the tensile strength of the resultant joints. From the tensile characteristics viewpoint, the greatest tensile strength value of 365 MPa is obtained at 1.5 MPa and 15 s. Finally, the role of microstructural features on tensile strength of resultant joints is discussed.
