TITLE:
Influence of Nanocrystalline Structure on Wear and Corrosion Behavior of Al-SiCP Composite
AUTHORS:
Jagannati Venumurali, Gaddam Bhanodaya Reddy
KEYWORDS:
Functionally Graded Al-SiCP Composite, Shot Peening, NC Structure, Wear, Corrosion
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.8 No.2,
March
25,
2020
ABSTRACT: Functionally
graded (FG) Al-SiCP composites fabricated via centrifugal casting are widely
used in automobile components particularly a brake rotor disc be-cause of its
high SiC fraction at the outer periphery. However, when operated in corrosive
environment like road deicing salts the disc is highly sensitive to the
corrosion due to high SiC fraction. But, the nanocrystalline (NC) structured
surfaces synthesized by severe plastic deformation (SPD) method have excel-lent
wear and corrosion resistance at the surface. Therefore, shot peening (SP) as a
SPD method conducted on one side of the stir casted FG Al composite having 10
wt% SiCP constant reinforcement in order to create NC structured surface. The
SP treatment continued for 70 s and 140 s durations. Thereafter, the surface
characteristics of the composite before and after SP were estimated by XRD and
then the composites were tested by wear and corrosion tests. The results
revealed that the SP for 140 s duration favors the induction of hardened layer,
higher grain refinement (NC structure) and dislocation density which promotes
the occurrence of high surface hardness, thus significantly improving its wear
properties. However, higher dislocation density resulted from longer duration
shown deterioration to the corrosion resistance. Whereas, the attained degree
of NC structure is more pronounced over dislocation density resulted after 70 s
SP duration, thereby composite showed excellent corrosion re-sistance. Thus,
the composite with 70 s duration possessed excellent corrosion and relatively
good wear properties too.