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For the first time, Zr702 coatings were deposited onto an Al6061 alloy using a high-pressure cold spray (HPCS) system. In this work, five different N2 process gas temperatures between 700 and 1100 °C were employed to understand the formation of cold sprayed (CS) Zr coatings and their feasibility for enhanced wear resistance. Results indicated that the N2 processing gas temperature of about 1100 °C enabled a higher degree of particle thermal softening, which created a dense, robust, oxide- and defect-free Zr coating. Across all CS Zr coatings, there was a refinement of crystallinity, which was attributed to the severe localized plastic deformation of the powder particles. The enhanced thermal boost up zone at the inter-particle boundaries and decreased recoverable elastic strain were accountable for the inter-particle bonding of the coatings at higher process gas temperatures. The flattening ratio (ε) increased as a function of temperature, implying that there was a greater degree of plastic deformation at higher N2 gas temperatures. The microhardness readings and wear volume of the coatings were also improved as a function of process gas temperature. In this work, the wear of the Al6061 alloy substrate was mainly plowing-based, whereas the Zr CS substrates demonstrated a gradual change of abrasive to adhesive wear. From our findings, the preparation of CS Zr coatings was a feasible method of enhancing the wear resistance of Al-based alloys. [ABSTRACT FROM AUTHOR]

Friction stir processing (FSP) was employed as a post-surface processing technique to modify the tribological and corrosion behavior of cold-sprayed (CS) 316L SS deposits. Results indicate that the effect of FSP induced an austenitic phase transformation due to the combination of frictional heat and plastic deformation. Consequentially, the friction of the CS deposit after FSP decreased by 8.3%. Similarly, the wear rate was reduced by 55.1%. These properties were improved mostly due to the closure of pores (yielding a 99.97% density) and localized grain refinement. Electrochemical measurements revealed that the corrosion rate was reduced by ∼65%. Also, the pitting corrosion resistance (E pit – E corr) increased, which can be majorly attributed to the densified surface and full austenitic phase transformation after FSP. Compared to the other samples, the highest polarization resistance at the corrosion potential (R pol) was obtained for the FSP CS 316L SS. Based on these findings, it can be inferred that FSP is a viable method to improve the tribological and corrosion behavior of CS 316L SS deposits. [Display omitted] • Cold sprayed steel was subjected to friction stir processing (FSP). • FSP led to notable grain size refinement and surface densification. • A full austenitic phase transformation was observed after FSP. • The influence of FSP resulted in a reduced friction and wear rate. • FSP reduced the propensity of pitting corrosion and passivation current density. [ABSTRACT FROM AUTHOR]