Friction stir cladding of commercially pure titanium on 304 stainless steel

In this research, commercially pure titanium-304 stainless steel (CP-Ti/304SS) bimetal was fabricated using the friction stir cladding process. The CP-Ti/SS304 bimetal is characterized using microstructural, mechanical properties, and corrosion resistance investigations. The results show that as the tool rotational speed decreases, the Ti layer’s thickness decreases at the bimetal interface. By reducing the tool’s rotational speed from 1000 to 800 rpm, the size of ultra-fine grains formed at the upper side of SS304 decreases from 1.2 to 0.2 μm. Also, an ( α + β )-Ti structure was formed at the bimetal interface under the influence of heat and plastic deformation. The maximum yield strength, ultimate tensile strength, and CP-Ti/SS304 bimetal elongation were determined as 688.1 ± 16.7 MPa, 858.3 ± 13.2 MPa, and 27.8 ± 5.1%, respectively, at a rotational speed of 1000 rpm and traverse speed of 10 mm/min. By increasing rotational speed, the corrosion voltage changes towards positive values and the corrosion current decreases.