Study On The Soldering Process Of Fe-based Amorphous And Aluminum Assisted By Ultrasonic Vibrations

Fe-baseed amorphous alloys are famous for their excellent soft magneticproperties, low magnetic loss and so on. However, it is difficult to fabricate largedimensions of amorphous materials because of their harsh formation conditions. Inthis work，it is focused on that how to overcome the problem of its size and extendthe applications of Fe-based amorphous alloys.Effects of ultrasonic vibrations on wetting properties between Fe77.5Si13.5B9amorphous alloys and solder were firstly studied, and the interface growth behaviorswere conducted. Then，for the first time，Fe77.5Si13.5B9amorphous alloy and1060Alwere soldered with each other by ultrasonic-assisted soldering process. Effects ofultrasonic vibrations on the evolution of the joint interfaces were explored.Wetting experiments showed that the spreading area increased with theincreasing of ultrasonic power and time；the wetting angle gradually decreased from46.5°to19.5°，indicating that the wetting properties were improved significantly.The growth pattern of intermetallic compounds（IMCs）was explored bythermal aging experiments. By calculating the growth rates of IMCs, the mode wasthe volume diffusion. The IMC was identified as FeZn13, the reason was the lowerelectronegativity of Fe and Zn elements than Sn, resulting in easier interact ion ofthem to form compounds. By estimation through the Arrhenius equation, the phaseactivation energy of Fe-Zn is approximately30.9kJ/mol.It was found that the interface of the aluminum alloy was eroded apparently.Adding ultrasonic vibrations, the interdiffusion between Zn and Al was promoted,and the formation of α-Al solid solution seemed to be easier. At the same time, arod-shaped Zn-riched phase was also crushed and dispersed in the joint matrix;regarding to the Sn-9Zn-0.5Ni solder, a Zn-riched phase and α-Al solid solutionco-existed in the joint matrix, a new phase granular NiAl3dispersed in the jointmatrix after the soldering process.According to the hardness tests, the hardness of the weld zone which wasformed by using the Sn-9Zn-0.5Ni solder was always higher than that of the Sn-9Znsolder, which was primarily due to the dispersed phase of NiAl3, which couldstrengthen the matrix. Meanwhile, compared with the joint formed withoutultrasonic vibrations, when the ultrasonic power was300W and the ultrasonic timewas60s, the hardness values in the weld zone were increased by15.3%and14.7%ifusing Sn-9Zn-0.5Ni solder and Sn-9Zn solder respectively. Micro-XRD results indicated that before and after the soldering process, Fe77.5Si13.5B9remained to beamorphous. Even the samples were heated at623K for60s, the magneticpermeability was only reduced by9.2%, indicating that the superior magneticproperties of Fe77.5Si13.5B9was preserved, which also showd that theultrasound-assisted soldering method can successfully realize a robust joint betweenFe77.5Si13.5B9amorphous alloy and1060Al.