Abstract
<jats:p>Introduction. To reduce the number of defects and improve the mechanical properties of components fabricated by wire arc additive manufacturing (WAAM), the application of deformation hardening operations during the synthesis process is promising. Wave deformation hardening enables the formation of a deep hardened layer, which is particularly important for hybrid WAAM processes where subsequent heating of the upper layers can lead to softening of previously deposited layers. A key parameter determining the effectiveness of wave deformation hardening is the temperature at which the synthesized material is subjected to the deformation hardening. The purpose of this study is to analyze the influence of the product temperature on the efficiency of wave deformation hardening for several advanced structural materials produced by the WAAM method. Methodology. The experiment involved the synthesis of samples, followed by furnace heating to a predetermined temperature (0.04C–19Cr–9Ni, 0.3C–1Cr–1Mn–1Si, 0.18C–1Cr–1Mn–1Si, and 0.09C–1.7Cr–1Mn–0.6Mo–1Ni–0.8Ti–0.015N: 300–900 °C; for the 97Al–3Mg alloy: 100–500°C), after which they were subjected to hardening. To evaluate the effectiveness of the method, microhardness (Vickers) profiles were measured as a function of depth through the hardened layer. Results and discussion. The study revealed a characteristic optimal temperature range for each material within which wave deformation hardening provides the maximum strengthening effect. For austenitic steel 0.04C–19Cr–9Ni, the greatest increase in hardness (up to 52%) was achieved when treated at 700 °C, attributed to the increased ductility of austenite and possible deformation-induced martensitic transformation; above 800 °C, recrystallization begins, reducing the effect. For medium-alloyed steels 0.3C–1Cr–1Mn–1Si, 0.18C–1Cr–1Mn–1Si, and 0.09C–1.7Cr–1Mn–0.6Mo–1Ni–0.8Ti–0.015N, the optimal range was 400–600 °C, with a maximum hardness increase of 34–50%; in this region, dynamic polygonization and carbide dispersion hardening actively occur, while recrystallization dominates at higher temperatures. For aluminum alloy 97Al–3Mg, the effective range was 100–300 °C, with an increase in hardness of up to 24%, corresponding to the recovery condition; at 400–500 °C, the hardness drops below the initial value due to complete recrystallization. The depth of the hardened layer exceeded 3 mm for steels and reached 8 mm for the aluminum alloy, significantly greater than achieved by conventional surface plastic deformation methods. An anomalous behavior was identified for steel 0.09C–1.7Cr–1Mn–0.6Mo–1Ni–0.8Ti–0.015N: after a decrease in hardness at 700–800 °C, an increase in hardness was observed at 900 °C, explained by secondary hardening due to the dissolution of coarse carbides and the precipitation of fine particles during cooling. The obtained data are in good agreement with known tempering and recrystallization temperatures for the materials studied. The results enabled the formulation of practical recommendations for selecting wave deformation hardening temperature conditions for integration into hybrid WAAM processes, depending on the material class, ensuring maximum improvement in both hardness and hardened layer depth for additively manufactured components.</jats:p>