Soldering aluminum alloys at low temperature have great potential to avoid softening of base metals.Pure Al was solderedwith pure tin assisted by ultrasound.The influence of primaryα(Al)on the microstructure of Al/Sn...Soldering aluminum alloys at low temperature have great potential to avoid softening of base metals.Pure Al was solderedwith pure tin assisted by ultrasound.The influence of primaryα(Al)on the microstructure of Al/Sn interface and its bonding strengthwas studied.It is found that the primaryα(Al)in liquid tin tends to be octahedron enclosed by Al{111}facet with the lowest surfacefree energy and growth rate.The ultrasonic action could increase the nucleation rate and refine the particles of primaryα(Al).For thelonger ultrasonic and holding time,a large amount of the octahedral primaryα(Al)particles crystallize at the Al/Sn interface.Thebonding interface exhibits the profile of rough dentation,resulting in an increment of bonding interface area and the effect ofmechanical occlusion.The bonding strength at interface could reach63MPa with ultrasonic time of40s and holding time of10min.展开更多
The interaction between exciton and confined longitudinal optical （LO） phonons, interface optical （IO） phonons in an asymmetric Ga1-xAlxAsIGaAslGao.TAlo.3As square quantum well is investigated. By applying the LLP...The interaction between exciton and confined longitudinal optical （LO） phonons, interface optical （IO） phonons in an asymmetric Ga1-xAlxAsIGaAslGao.TAlo.3As square quantum well is investigated. By applying the LLP-like transformation and variational approach, the numerical results are obtained as functions of the well width and asymmetric-degree of well. The exciton-optical phonons interaction-energy has a minimum value with the increase of the well width. It is demonstrated that the LO-phonon energy-contribution increases while the IO-phonon contribution decreases as the well width increases gradually. The energy-contribution of LO-phonon in symmetric and asymmetric square quantum well does not have too much difference, but the IO-phonon contribution varies apparently. The exciton binding-energy monotonically decreases with the increase of the well width and is proportional to the left-barrier height.展开更多
基金Project(51435004)supported by the National Natural Science Foundation of China
文摘Soldering aluminum alloys at low temperature have great potential to avoid softening of base metals.Pure Al was solderedwith pure tin assisted by ultrasound.The influence of primaryα(Al)on the microstructure of Al/Sn interface and its bonding strengthwas studied.It is found that the primaryα(Al)in liquid tin tends to be octahedron enclosed by Al{111}facet with the lowest surfacefree energy and growth rate.The ultrasonic action could increase the nucleation rate and refine the particles of primaryα(Al).For thelonger ultrasonic and holding time,a large amount of the octahedral primaryα(Al)particles crystallize at the Al/Sn interface.Thebonding interface exhibits the profile of rough dentation,resulting in an increment of bonding interface area and the effect ofmechanical occlusion.The bonding strength at interface could reach63MPa with ultrasonic time of40s and holding time of10min.
基金supported by the National Natural Science Foundation of China (Grant No. 10574011)
文摘The interaction between exciton and confined longitudinal optical （LO） phonons, interface optical （IO） phonons in an asymmetric Ga1-xAlxAsIGaAslGao.TAlo.3As square quantum well is investigated. By applying the LLP-like transformation and variational approach, the numerical results are obtained as functions of the well width and asymmetric-degree of well. The exciton-optical phonons interaction-energy has a minimum value with the increase of the well width. It is demonstrated that the LO-phonon energy-contribution increases while the IO-phonon contribution decreases as the well width increases gradually. The energy-contribution of LO-phonon in symmetric and asymmetric square quantum well does not have too much difference, but the IO-phonon contribution varies apparently. The exciton binding-energy monotonically decreases with the increase of the well width and is proportional to the left-barrier height.
