Dissertation Defence: Development and Characterization of in-situ Reinforced TiC-High Manganese Steel Particle Reinforced Metal Matrix Composite
July 14 at 9:00 am - 1:00 pm
Abhinav Karanam, supervised by Dr. Lukas Bichler, will defend their dissertation titled “Development and Characterization of in-situ Reinforced TiC-High Manganese Steel Particle Reinforced Metal Matrix Composite” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical Engineering.
An abstract for Abhinav Karanam’s dissertation is included below.
Examinations are open to all members of the campus community as well as the general public. This examination will be offered in hybrid format. Please email lukas.bichler@ubc.ca to receive the Zoom link for this exam.
Abstract
The increasing demand for mineral resources, particularly critical minerals, along with the need to increase the efficiency of mining operations continue to drive advances in mining operations. A key component of supporting these advances is the need to increase the wear resistance of materials used in comminution circuit equipment. One of the most cost-effective methods to improve the wear life is by replacing monolithic alloys with metal matrix composites, especially particle-reinforced metal matrix composites (PRMMCs). This study aimed to develop in-situ titanium carbide (TiC)-reinforced high-manganese (Mn) steel alloy composites via conventional metal casting route. The effect of alloy modification via the addition of titanium (Ti) on the microstructural evolution and tribomechanical behaviour of the alloy was investigated.
The results of the microstructural evolution revealed that the addition of Ti to the alloy resulted in the in-situ formation of homogeneously distributed TiC particles during solidification. In the as-cast condition, the TiC particles facilitated grain refinement through heterogeneous nucleation. Additional grain refinement of the composite material was observed after heat treatment. In-situ observation of the microstructure evolution up to 1125°C confirmed the stability of the formed TiC particles, and also revealed a potentially new mechanism of grain refinement during a solution heat treatment.
Room temperature Charpy impact toughness testing of the virgin high-Mn steel and in-situ TiC reinforced composite was performed. The results suggest that the refinement of the austenitic grains, facilitated by the in-situ TiC particles, dispersion strengthening, and other microstructural factors contributed to a significant improvement in the impact toughness of the composite. A detailed investigation of the strengthening mechanisms contributing to the observed enhancement in the composite material’s impact toughness revealed the simultaneous contributions of Orowan strengthening, load-transfer strengthening, and increased grain-boundary strengthening. TWIP and TRIP effects enhanced the composite material’s impact properties.
Dry sliding reciprocating wear testing of the two materials revealed a significant improvement in the composite’s wear resistance due to the formation of the in-situ TiC particles. The composite experienced a 15%, 17%, and 23% reduction in volume loss at sliding distances of 300m, 600m, and 900m, respectively. The observed improvement in the wear resistance of the composite material was associated to the TiC induced grain refinement, dispersion strengthening and shielding of the matrix by the TiC particles and increased work hardening with Ti addition.
