DRY SLIDING WEAR BEHAVIOR OF NANO and MICRON PARTICLES REINFORCED P/M BASED METAL MATRIX COMPOSITES

ABSTRACT
Powder Metallurgy (P/M) based Metal Matrix Composites (MMCs) has emerged as a
class of materials capable of advanced structural, aerospace and automotive
applications in recent years. In spite of various process and property advantages, they
have one major disadvantage namely poor wear resistance. This restricts the use of
these MMCs, for wear resistant applications. Use of reinforcement of ceramic hard
particles namely SiC and Al2O3 , to improve wear properties in MMCs are common in
spite of its high cost and poor compatibility with base metal matrix. Recently, interest in
use of intermetallic particles in MMCs for tribological applications has grown
significantly. The principal advantage of intermetallic composites is the metal-like
properties of the matrix. Also, they are attractive in tribological applications not only for
their intrinsic properties such as hardness, stability, wear resistance etc. but also
because of their compatibility with metallic matrices. Hence, the present investigation
aims at studying the influence of mechanically alloyed nano iron aluminide intermetallic
particles and micron alumina ceramic particles on the wear behavior of P/M based
SS316L metal matrix composites were studied using a pin-on-disk wear testing
machine under dry sliding condition. Both, iron aluminide and alumina were used as
particle reinforcement with 10 and 20 % volume in the matrix. The composites were
prepared by mixing and cold compacting followed by sintering SS316L at 1250°C. The
presence and distribution of Fe3Al and Al2O3 phases on the matrix were identified. The
experimental results indicated improvement in dry sliding wear properties of MMCs
compared to their plain alloys. It also revealed that unreinforced SS316L showed lower
wear resistance, while the composites with Fe3Al were found superior during longer
sliding conditions. Alumina reinforced SS316L based MMCs impart good wear
resistance only, for shorter sliding distances and the beneficial effects of Al2O3 tend to
decrease as the sliding distance increases. Wear tracks were characterized by SEM
techniques to identify the possible wear mechanisms for the composites studied.