Corrosion study on chill casting effect on aluminium A356 reinforced with Hematite metal matrix composites

Abstract

In this article, an attempt have been made through investigate the effect of copper chill on Aluminium Metal Matrix Composites (AMMCs), and also to explore the corrosion resistance of the prepared Al A356-Hematite particulate metal matrix composites, which is cast through sand casting practice without and with copper chills at ends to get isotropic and homogeneous material properties under liquid metallurgical manner, by varying weight fractions of Hematite particulates assortments from 0 wt% −12 wt% in segments about 3 wt%. The test samples were prepared as per ASTM criteria. The prepared specimens were subjected to corrosion test and Micrographic analysis. The experiments were conducted to study the corrosion rate by weight-loss method, the specimens were soaked in 3.5% NaCl solution with a time intervals of 24 h to 96 h in steps of 24 h. Result shows that, the copper chill A356-Hematite composites shows lesser corrosion rate compare to without copper chill. Micrographic investigation has been executed using XRD (X-Ray Diffraction) patterns and SEM (Scanning Electron Microscope) photos. The presence of Hematite elements was conformed by XRD pattern and also revealed that the even distribution of Hematite elements in the A356 matrix alloy of composite casted with copper chills. It was also pragmatic that fine-grained structure is obtained due to rapid cooling which influences in enlightening the corrosion resistance of the composites with copper chills. And also due to an increased content of reinforcement in both without and with copper chill composites results in significant enhancement in corrosion resistance. The Copper chill specimens shows higher corrosion resistance than As-cast specimens.