Date of Award

January 2017

Document Type

Thesis

Degree Name

Master of Engineering (MEngr)

Department

Mechanical Engineering

First Advisor

Surojit Gupta

Abstract

This research has focused on the design and development of novel multifunctional MAX reinforced ceramics (MAXCERs). These MAXCERs were manufactured with 1-50 vol% ratios of ceramics to MAX phases. Chapter II reports on the synthesis and tribological behavior of Ti3SiC2 matrix composites by incorporating (1 and 6 vol%) Al2O3, (1 and 5 vol%) BN, and (1 and 5 vol%) B4C ceramic particulate additives in the matrix. All the composites were fabricated by pressureless sintering by using ~1 wt% Ni as a sintering agent at 1550 oC for 2 hours. SEM and XRD studies showed that Al2O3 is relatively inert in the Ti3SiC2 matrix whereas BN and B4C reacted significantly with the Ti3SiC2 matrix to form TiB2. Detailed tribological studies showed that Ti3SiC2-1wt%Ni (baseline) samples showed dual type tribological behavior where the friction coefficient (Õ© was low (~0.2) during stage 1, thereafter Õ increased sharply and transitioned into stage 2 (~0.8). The addition of Al2O3 as an additive had little effect on the tribological behavior, but the addition of B4C and BN was able to enhance the tribological behavior by increasing the transition distance (TD). Chapter III reports on the synthesis and tribological behavior of TiB2 matrix composites by incorporating (10, 30, and 50 vol%) Ti3SiC2 ceramic particulate additives in the matrix. The fabrication parameters were similar to the Ti3SiC2 samples from Chapter II. There was minimal reaction between the TiB2 and the Ti3SiC2. Detailed tribological studies showed that TiB2 (baseline) and TiB2-10%Ti3SiC2 samples showed an average Õ of ~0.29 and ~0.28, respectively. TiB2-30%Ti3SiC2 and TiB2-50%Ti3SiC2 showed dual-type tribological behavior where Õ was low (~0.25) during stage 1, thereafter Õ increased gradually and transitioned into stage 2 (~0.6). Low wear rates were seen for all samples.

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