The influences of pin offset on the formation, microstructure and mechanical properties of friction stir welded joint of Ti6 Al4 V and AZ31 B Mg dissimilar alloys were investigated. The results show that sound joints ...The influences of pin offset on the formation, microstructure and mechanical properties of friction stir welded joint of Ti6 Al4 V and AZ31 B Mg dissimilar alloys were investigated. The results show that sound joints are obtained at different offsets. With the offset decreasing from 2.5 to 2.1 mm, the number of Ti alloy fragments is increased, and the stir zone(SZ) is enlarged and the grains in SZ become coarser. A hook-like structure is formed at the Mg/Ti interface and its length is increased with the decrease in pin offset. The Al element has an enrichment trend at the Ti alloy side near the Mg/Ti interface when the offset is decreased, which is beneficial to the bonding of the interface. An Al-rich layer with a thickness of 3–5μm forms at the offset of 2.1 mm. All the joints fracture at the interface and present a mixed ductile-and-brittle fracture mode. The joint tensile strength is increased with the offset decreasing from 2.5 to 2.1 mm, and the maximum tensile strength of 175 MPa is acquired at the offset of 2.1 mm.展开更多
A new structure of 4H-silicon carbide （SIC） merged PiN-Schottky （MPS） diodes with offset field-plate （FP） as edge termination is developed. To understand the influences of 4H-SiC MPS diodes with offset FP on the...A new structure of 4H-silicon carbide （SIC） merged PiN-Schottky （MPS） diodes with offset field-plate （FP） as edge termination is developed. To understand the influences of 4H-SiC MPS diodes with offset FP on the characteristics, simulations have been done by using ISE TCAD. Related factors of offset FP have been studied as well to optimise the reverse characteristics of 4H SiC MPS diodes. The simulation results show that the device using offset FP can create a higher blocking voltage under reverse bias as compared with that using field guard rings. Besides, the offset FP does not cause any extra steps in the manufacture of MPS diodes.展开更多
基金supported by the National Natural Science Foundation of China (No. 51705339)the Aeronautical Science Foundation of China (No. 20171125002)
文摘The influences of pin offset on the formation, microstructure and mechanical properties of friction stir welded joint of Ti6 Al4 V and AZ31 B Mg dissimilar alloys were investigated. The results show that sound joints are obtained at different offsets. With the offset decreasing from 2.5 to 2.1 mm, the number of Ti alloy fragments is increased, and the stir zone(SZ) is enlarged and the grains in SZ become coarser. A hook-like structure is formed at the Mg/Ti interface and its length is increased with the decrease in pin offset. The Al element has an enrichment trend at the Ti alloy side near the Mg/Ti interface when the offset is decreased, which is beneficial to the bonding of the interface. An Al-rich layer with a thickness of 3–5μm forms at the offset of 2.1 mm. All the joints fracture at the interface and present a mixed ductile-and-brittle fracture mode. The joint tensile strength is increased with the offset decreasing from 2.5 to 2.1 mm, and the maximum tensile strength of 175 MPa is acquired at the offset of 2.1 mm.
基金Project supported by Applied Materials Innovation Fund (Grant No. XA-AM-200702)the 13115 Innovation Engineering of Shaanxi Province,China (Grant No. 2008ZDKG-30)
文摘A new structure of 4H-silicon carbide （SIC） merged PiN-Schottky （MPS） diodes with offset field-plate （FP） as edge termination is developed. To understand the influences of 4H-SiC MPS diodes with offset FP on the characteristics, simulations have been done by using ISE TCAD. Related factors of offset FP have been studied as well to optimise the reverse characteristics of 4H SiC MPS diodes. The simulation results show that the device using offset FP can create a higher blocking voltage under reverse bias as compared with that using field guard rings. Besides, the offset FP does not cause any extra steps in the manufacture of MPS diodes.
