The performance of a Co-based alloy tool in the friction stir welding of TA5 alloy

Friction Stir Welding/Processing of Various Metals with Working Tools of Different Materials and Its Peculiarities for Titanium Alloys: A Review

“…As stated previously, friction stir welding and processing are based on the effect of adhesive friction between tool and material, plastic deformation, superplastic metal flow, and other related processes [98][99][100][101][102][103][104][105][106][107][108]. Welding and processing processes are almost identical, and the main difference is the junction line between the plates during welding (Figure 1).…”

The Regularities of Metal Transfer by a Nickel-Based Superalloy Tool during Friction Stir Processing of a Titanium Alloy Produced by Wire-Feed Electron Beam Additive Manufacturing

“…When considering the features of the interaction between tool and material in work [22], it can also be observed that in different regions of the transfer layer, the material of the stir zone can exhibit both laminar and vortex structure. Despite the fact that friction stir processing of titanium alloy shows tendencies of intensive diffusion interaction with tools made of cobalt [26], nickel [22,27], boron nitride [28], hard alloys [29], and many different materials [30], the mechanism of metal transfer along the tool contour remains unchanged, and the use of stop-action technique allowed us to visualize its features in more detail in this work.…”

Enhancing the tribological properties of pure Ti by pinless friction surface stirring

“…Damaging the FSP tool not only deteriorates its performance but also may result in loss of surface quality and incorporation of inclusions into the workpiece [22]. Therefore, many efforts have been made to develop new potent FSP tool materials having high thermal durability/wear resistance and low sensitivity to abrupt temperature changes such as polycrystalline CBN, W-Re alloy, Mo-based alloy, and W-La [21,23]. However, despite their improved performance, these materials are generally expensive and fabricated through costly and tedious processes [22,23].…”

“…According to previous investigations, FSP can significantly improve the surface properties of CP-Ti by promoting the formation of ultrafine grains and increasing the density of dislocations and volume fraction of Widmanstätten structure [15,16,[18][19][20]. Nonetheless, due to the high melting point (1668°C) and high flow stress of CP-Ti, the conventional FSP tools made of tool steel or WC are subjected to high temperatures and rather high loads [21]. Thus, severe damage/wear by hot adhesion and micro-constituents inter-diffusion mechanisms is inevitable [21,22].…”

“…Nonetheless, due to the high melting point (1668°C) and high flow stress of CP-Ti, the conventional FSP tools made of tool steel or WC are subjected to high temperatures and rather high loads [21]. Thus, severe damage/wear by hot adhesion and micro-constituents inter-diffusion mechanisms is inevitable [21,22]. Damaging the FSP tool not only deteriorates its performance but also may result in loss of surface quality and incorporation of inclusions into the workpiece [22].…”