Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properti...Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properties of welded samples by preventing the fracture location at the Mg/Al interface. Friction stir welding was performed to join Mg to Al at different rotational and travel speeds. The microstructure of the welded samples showed the IMCs layers containing Al12Mg17(γ) and Al3Mg2(β) at the welding zone with a thickness(< 3.5 μm). Mechanical properties were mainly affected by the thickness of the IMCs, which was governed by welding parameters. The highest tensile strength was obtained at 600 r/min and 40 mm/min with a welding efficiency of 80%. The specimens could fracture along the boundary at the thermo-mechanically affected zone in the Mg side of the welded joint.展开更多
Friction stir processing(FSP)can be used to improve surface composites.In this study,a modified method of FSP called friction stir vibration processing(FSVP)was applied to develop a surface composite on AZ91 magnesium...Friction stir processing(FSP)can be used to improve surface composites.In this study,a modified method of FSP called friction stir vibration processing(FSVP)was applied to develop a surface composite on AZ91 magnesium alloy.In this technique,the workpiece is vibrated normal to the processing direction.The results illustrated that compared with the FSP method,the FSVP caused a better homogeneous distribution of SiC particles in the microstructure.The results also showed that matrix grains of friction stir vibration processed(FSV-processed)samples((26.43±2.00)μm)were finer than those of friction stir processed(FS-processed)specimens((39.43±2.00)μm).The results indicated that the ultimate tensile strength(UTS)of FSV-processed specimens(361.82 MPa)was higher than that of FS-processed specimens(324.97 MPa).The higher plastic strain in the material during FSVP,due to workpiece vibration,resulted in higher dynamic recrystallization,and consequently,finer grains were developed.The elongation and formability index of the FSV-processed specimen(16.88%and 6107.52 MPa·%,respectively)were higher than those of the FS-processed sample(15.24%and 4952.54 MPa·%,respectively).Moreover,the effects of FSVP were also found to intensify as the vibration frequency increased.展开更多
基金Universiti Kebangsaan Malaysia for supporting this research project through the research funding (AP-2015-016)
文摘Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properties of welded samples by preventing the fracture location at the Mg/Al interface. Friction stir welding was performed to join Mg to Al at different rotational and travel speeds. The microstructure of the welded samples showed the IMCs layers containing Al12Mg17(γ) and Al3Mg2(β) at the welding zone with a thickness(< 3.5 μm). Mechanical properties were mainly affected by the thickness of the IMCs, which was governed by welding parameters. The highest tensile strength was obtained at 600 r/min and 40 mm/min with a welding efficiency of 80%. The specimens could fracture along the boundary at the thermo-mechanically affected zone in the Mg side of the welded joint.
基金the Amirkabir University of Technology(AUT)Sharif University of Technologythe National Elites Foundation of Iran for their support during this research。
文摘Friction stir processing(FSP)can be used to improve surface composites.In this study,a modified method of FSP called friction stir vibration processing(FSVP)was applied to develop a surface composite on AZ91 magnesium alloy.In this technique,the workpiece is vibrated normal to the processing direction.The results illustrated that compared with the FSP method,the FSVP caused a better homogeneous distribution of SiC particles in the microstructure.The results also showed that matrix grains of friction stir vibration processed(FSV-processed)samples((26.43±2.00)μm)were finer than those of friction stir processed(FS-processed)specimens((39.43±2.00)μm).The results indicated that the ultimate tensile strength(UTS)of FSV-processed specimens(361.82 MPa)was higher than that of FS-processed specimens(324.97 MPa).The higher plastic strain in the material during FSVP,due to workpiece vibration,resulted in higher dynamic recrystallization,and consequently,finer grains were developed.The elongation and formability index of the FSV-processed specimen(16.88%and 6107.52 MPa·%,respectively)were higher than those of the FS-processed sample(15.24%and 4952.54 MPa·%,respectively).Moreover,the effects of FSVP were also found to intensify as the vibration frequency increased.
