Tuning the microstructure, mechanical properties, and tribological behavior of in-situ VCp-reinforced Fe-matrix composites via manganese-partitioning treatment

Mn (Manganese)-partitioning treatment plays an important role in stabilizing retained austenite of in-situ VCp (vanadium carbide particle) reinforced iron (Fe) matrix composite (VCFC). The effects of Mn-partitioning treatment on microstructure, mechanical properties, and tribological behavior of in-situ VCp-reinforced Fe matrix composite were studied. The experimental results indicated that a certain amount of retained austenite was formed via a series of heat treatments, such as austenitizing, quenching and partitioning treatment (Q&P treatment). And Mn-partitioning treatment was performed to strongly stabilize the retained austenite at room temperature. Meanwhile, the ratio of vanadium carbide was adjusted during the process of heat treatment. The area ratio of VC particles gradually increased with increasing Mn-partitioning temperatures, the maximum value of 15.88 % was discovered with Mn-Partitioning temperature of 750 degrees C. But the area ratio of vanadium carbide first rose and then fell with increasing Mn-partitioning times, the minimum value of 11.2 % existed within Mnpartitioning time of 45 min. In this work, mechanical properties and wear resistance depend on the existence of retained austenite and particle characteristics. TRIP (Transformation-Induced Plasticity) effect, phase transformation from retained austenite (face-centered-cubic structure, FCC) to martensite (body-centered-cubic structure, BCC) was occurred under a certain loads. Thus contradictions between the hardness, tensile strength and wear resistance could be solved. By means of heat treatment, micro-hardness of 719.9 HV and tensile strength of 288.8 MPa with Mn-partitioning temperature of 700 degrees C and Mn-partitioning time of 30 min, and accompanied with wear rate of 1.12x10(-6) mm(3)/(N m), therefore, Mn-partitioning temperature of 700 degrees C and Mn-partitioning time of 30 min was considered to be a better process parameters.