Fabrication of LM 25/WC functionally graded composite for automotive applications and investigation of its mechanical and wear properties

Abstract

Functionally graded Al LM 25/10 wt% WC composite of dimension [ out 100 9 [ in 60 9 100 mm was fabricated using centrifugal casting method. Mechanical and tribological properties of outer (1 mm), middle (11 mm) and inner (18 mm) layers from outer periphery of hollow cylindrical component were studied. Microstructural investigation revealed maximum distribution of reinforcements in outer layer, followed by middle and inner layer. Outer periphery had the highest hardness while outer zone displayed better tensile characteristics. Fractographs revealed brittle nature at outer layer due to high concentration of WC particles while a combined mode of ductile and brittle failure was observed at inner layer. Wear rate of outer layer increased linearly with increasing applied load, nonlinearly with increasing sliding velocity and sliding distance. Worn surface morphologies revealed fine and shallow grooves at outer layer ensuring mild material removal. Mild to severe wear transition was observed with increasing applied load. Mechanically mixed layer formation was observed with increasing velocity. This composite having enhanced mechanical and wear properties at outer zone is suitable for automotive applications such as pistons, liners, brake disks and bearings.

A review on fabrication and characteristics of functionally graded aluminum matrix composites fabricated by centrifugal casting method

“…The strengthening is due to dislocation motion in the metal being impeded by the presence of small, hard particles. The Orowan bypassing [50][51][52][53] of the particle by the movement of dislocation increases the material's strength:…”

“…Functionally graded aluminum matrix composite of LM25 alloy with 10 wt%WC reinforcement was synthesized by Jojith and Radhika [53] using an ex-situ horizontal centrifugal casting process under 1000 rpm. The investigation included microstructure, mechanical, and wear characterization of FGAMC.…”

“…Fig.10Variation in hardness, tensile, and yield strength at different locations of LM25-10 wt% WC FGAMC[53] …”

Enhancing the Mechanical and Reciprocating Wear Behavior of Functionally Graded A359 Aluminium Alloy Through Heat Treatment

“…The wear behavior of Al-Si alloy depends mostly on process parameters such as load, frequency, sliding distance, mechanical properties, composition and interfacial conditions [13,14]. Gomes et al and Rajeev et al confirms that under optimum conditions, Al-Si alloys frictional force and wear rate increases with increase in load [15,16] whereas under the influence of higher sliding speeds, a non-linear decrease in wear properties are observed [17,18]. As steel is the widely used material and aluminium is the successor, the aluminium-steel tribo-pair is preferred for studying wear [19].…”

Predicting the effect of machining parameters on turning characteristics of AA7075/TiB2 in situ aluminum matrix composites using empirical relationships

“…The lighter aluminum alloys reinforced with a range of ceramic particulates, classified as aluminum matrix composites (AMCs), offers a solution to increase the working range of materials. Many characteristics of AMCs including enhanced performance at elevated temperature, superior room-and high-temperature wear behavior and improved specific strength are the driving factors to substitute them for conventional materials [1,2]. TiB 2 ceramic particle possesses a blend of mechanical, thermal and electrical properties which make them a good candidate for reinforcing AMCs [3,4].…”