OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 2 2025 Fig. 11. Microhardness as a function of processing time for cast and additively manufactured ZhS6U alloy samples after low frequency impact processing Fig. 12. Microhardness as a function of processing time for cast and additively manufactured ZhS6U alloy samples after high frequency impact processing The results of the scratch test performed after LF impact treatment of nickel alloy samples produced by casting and EBAM are presented in Fig. 13. The coefficient of friction during scratch testing with a gradually increasing load (from 0.5 to 30 N) of nickel alloy samples after LF impact treatment (10–20 seconds) either remains at the level of the initial material (Fig. 13, black line) or increases. At the maximum LF treatment duration (40 seconds), the coefficient of friction reaches its minimum value (Fig. 13, a, b). However, after 40 seconds of treatment, significant scatter in the coefficient of friction is observed depending on the scratch path length during the test, which is caused by surface irregularities. Scratch testing under a constant load of 20 N also reveals a large scale of the coefficient of friction due to analyzed surface irregularities (Fig. 13, c, d). Fig. 13 e, f shows a final comparison of cast and additively manufactured nickel alloy samples after LF impact treatment, based on scratch test results under constant load, in the form of a dependence of averaged friction coefficients. As can be seen on dependences for the cast nickel alloy after LF treatment, the coefficient of friction generally increases, with a decrease observed only after the longest treatment time (40 seconds), where the value drops lower than the initial condition (Fig. 13, e). Conversely, for the alloy produced by EBAM, LF impact treatment leads to a decrease compared to the initial condition more than two times – from 0.19 to 0.075. The results of the scratch test performed after HF impact treatment of nickel alloy samples produced by casting and EBAM are presented in Fig. 14. The coefficient of friction under a gradually increasing load (0.5 to 30 N) of cast alloy samples after HF impact treatment generally remains at the level of the initial material (Fig. 14, black line) or increases, like for the additive sample after 10 minutes of HF treatment. When scratch testing samples after HF impact with a constant load of 20 N, a large spread of friction coefficient values is observed (Fig. 14, c, d), caused by surface roughness after treatment. Fig. 14 e, f show
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