Characterization of Al-Al2Cu Functionally Graded Material Produced by Using Horizontal Centrifugal Casting

In this paper, characterizations of thick-walled functionally graded (FG) cylinder containing Al-26 wt.% Cu fabricated through horizontal centrifugal casting technique are investigated. Field emission scanning electron microscopy (FESEM) in conjunction with image analyser software and energy dispersion spectroscopy (EDS) is applied to measure the variations of constituent phase’s content and elemental ratios along radial direction, respectively. Distributions of the FG properties are measured through hardness, coefficient of thermal expansion (CTE), elastic modulus (E) and yield strength (σy) along radial direction to investigate the mechanical and physical properties corresponding to the variations in microstructure. In addition, the variations of wear rate along thickness are evaluated through a series of dry sliding wear tests using the pin-on-disk wear machine. Moreover, scanning electron microscopy (SEM) is employed to characterize the worn-out surfaces and morphology of wear debris in order to clarify the dominant operative wear mechanism. Results showed that Al2Cu content gradually decreases from the inner wall containing 33.3 vol. % to outer wall containing 26.4 vol. % in the FG cylindrical shell. The elastic modulus and yield strength measured through compression tests reveal that these mechanical properties are limited up to certain value of Al2Cu. The optimum value of Al2Cu content for studied Al-Al2Cu FG is obtained almost 31 vol. %.

Microstructure; Vickers hardness; Wear resistance; Yield strength