Ultrasonic-assisted soldering of 2024 aluminum alloys using a filler metal of Zn-5Al alloy was investigated at the temperature of 400 ℃,which is lower than the solution strengthening temperature of Al-Cu alloys.The u...Ultrasonic-assisted soldering of 2024 aluminum alloys using a filler metal of Zn-5Al alloy was investigated at the temperature of 400 ℃,which is lower than the solution strengthening temperature of Al-Cu alloys.The ultrasonic vibration with power of 200 W and vibration amplitude of 15 μm at the frequency of 21 kHz was applied on the top samples.The ultrasonic vibration promoted the dissolution of Al elements in the base metal.The reduction of volume fraction of the eutectic phases in the bonds was investigated by increasing ultrasonic vibration time.As the ultrasonic vibration time increased from 3 s to 30 s,the volume fraction of the eutectic phase in the bonds decreased from 12.9% to 0.9%,and the shear strength of the joints was up to 149-153 MPa,increased by 20%.The improvement of the mechanical properties of joints was discussed based on the modulus and hardness of the phases in the bonds and the fracture of the joints.展开更多
The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction,%) alloy upon successive heating (the rate of heating is 5 ℃/min) have been st udied by means of ρ—T curve,shape memory effect measuremen...The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction,%) alloy upon successive heating (the rate of heating is 5 ℃/min) have been st udied by means of ρ—T curve,shape memory effect measurement,optical met allographical observation and X-ray diffraction. The first abnormal reverse sha pe memory effect occurs when the tested alloy is heated to the temperature below 320 ℃;when it is heated to the temperature between 320 ℃ and 450 ℃,the forward shape memory effect occurs;in the two stages,the shape of the sample r emains the same as that in the furnace when it is taken out from the furnace and air-cooled;when the tested alloy is heated to the temperature above 450 ℃,the shape of the sample remains unchanged during heating,but the second reverse shape memory effect occurs after it is air-quenched.展开更多
基金Projects(51075104,50975054) supported by the National Natural Science Foundation of ChinaProject(2010RFQXG020) supported by the Harbin Excellence Talents Program,China
文摘Ultrasonic-assisted soldering of 2024 aluminum alloys using a filler metal of Zn-5Al alloy was investigated at the temperature of 400 ℃,which is lower than the solution strengthening temperature of Al-Cu alloys.The ultrasonic vibration with power of 200 W and vibration amplitude of 15 μm at the frequency of 21 kHz was applied on the top samples.The ultrasonic vibration promoted the dissolution of Al elements in the base metal.The reduction of volume fraction of the eutectic phases in the bonds was investigated by increasing ultrasonic vibration time.As the ultrasonic vibration time increased from 3 s to 30 s,the volume fraction of the eutectic phase in the bonds decreased from 12.9% to 0.9%,and the shear strength of the joints was up to 149-153 MPa,increased by 20%.The improvement of the mechanical properties of joints was discussed based on the modulus and hardness of the phases in the bonds and the fracture of the joints.
文摘The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction,%) alloy upon successive heating (the rate of heating is 5 ℃/min) have been st udied by means of ρ—T curve,shape memory effect measurement,optical met allographical observation and X-ray diffraction. The first abnormal reverse sha pe memory effect occurs when the tested alloy is heated to the temperature below 320 ℃;when it is heated to the temperature between 320 ℃ and 450 ℃,the forward shape memory effect occurs;in the two stages,the shape of the sample r emains the same as that in the furnace when it is taken out from the furnace and air-cooled;when the tested alloy is heated to the temperature above 450 ℃,the shape of the sample remains unchanged during heating,but the second reverse shape memory effect occurs after it is air-quenched.
