Joint interface during arc milling brazing of aluminum alloy to low carbon steel with cutter milling at various rotation speeds

In this study, 5052 aluminum alloy and Q235 steel were joined by a new way of arc milling brazing, with the Zn15%Al filler metal and no use of flux. Effect of rotation speed on mechanical properties and microstructure of joint interface was investigated. The results show that increasing rotation speed is in favor of formation of weld and spread of filler metal on substrate. The fine grain with homogeneous composition in brazed seam can be realized by the stronger stirring in pool induced by milling at more higher rotation speed. And, a composite joint reinforced with needle-like or block-like Fe–Al–Zn intermetallic compounds (IMCs) particle can be obtained by arc milling brazing, which comes from the reaction between steel scrape and Zn–Al filler alloy. The test on strength of joint interface shows that with the increase in rotation speed, there is a peak value in variation ranges of strength of joint interface. This is to say, when rotation speed is 2720 r·min⁻¹, the strength of joint has maximum value (182.01 MPa). Moreover, a thin and discontinuous IMCs layer at joint interface can be obtained by increasing rotation speed. But at a low or high rotation speed, there also is a crack at joint interface, which weakens the strength of joint interface. Only at 2720 r·min⁻¹, a good joint interface without an obvious crack can be realized.