Abstract:When welding aluminum-steel joints using continuous drive friction welding, the welding end face has the characteristic of rotating around the axis, and the phenomenon of uneven linear velocity along the radius direction will occur during welding, resulting in uneven friction torque and heat production. At the same time, because the dissolution rate between aluminum and steel is low, this will lead to the formation of a non-uniform aluminum-steel intermetallic compound at the joint interface, which affects the overall mechanical performance of the joint. The cold spray deposition Si interlayer can achieve good bonding with aluminum and steel, reduce the production of brittle Fe-Al intermetallic compounds, form a good performance Fe-Al-Si intermetallic compound, and change the joint bonding method. In this paper, cold spraying method was used to deposit Si powder on the end face of Q235 steel rod to form a 20um thick interlayer, and then continuous drive friction welding was used to weld with a 1060 aluminum rod. The effect of adding the Si interlayer on the friction torque, welding temperature, mechanical properties of the joint, and the morphology and properties of the interface intermetallic compound was compared and analyzed. The results showed that the addition of the Si interlayer reduced the friction coefficient of the aluminum/steel interface, reduced the friction torque and peak temperature of the welded joint, and further reduced the thickness of the intermetallic compound layer. The interface morphology was interlaced with each other, and the joint had mechanical interlocking, which increased the contact area. The intermetallic compound was mainly composed of Fe2Al5 and Fe3Al replaced by Al2Fe2Si3, Al0.5Fe3Si0.5 with better mechanical properties. The average bending angle of the joint increased by 59°, and its toughness was significantly improved, and the uniformity of the mechanical properties was reduced.