Abstract
In this research, different ratios (1, 3, and 5 mass%) of chromium carbide (Cr₃C₂) powders were added to Vanadis 4 alloy steel powders. The various components of the powders underwent vacuum sintering at 1235, 1250, and 1265 °C for 1 h, respectively. The heat treatment process included quenched, sub-zero, and tempering treatment afterward. The results showed that the alloy with the addition of 5 mass% Cr₃C obtained the optimal mechanical properties after sintering at the temperature of 1250 °C for 1 h. Meanwhile, the apparent porosity decreased to 0.04 %; the transverse rupture strength (TRS) and hardness reached 1821.2 MPa and 82.4 HRA. However, the hardness declined slightly to 82.3 HRA, but the TRS substantially increased to 2085.0 MPa. The decrease in hardness could be ascribed to the release of internal stress after the tempering process. Significantly, the alloy with a series of heat treatment processes was effective in enhancing strengthening TRS of the Vanadis 4 composites.

Key words
chromium carbide, Vanadis 4 alloy steel, vacuum sintering, porosity, transverse rupture strength, sub-zero treatment

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