Effect of Ageing Temperature on the Mechanical Properties of Al-6Si-0.5Mg Cast Alloys with Cu Additions Treated by T6 Heat Treatment

A Hossain,A S W Kurny

doi:10.13189/ujms.2013.010101

Abstract

Effect of artificial ageing temperature on the mechanical properties of Al-6Si-0.5Mg alloy containing 0.5 - 4 wt% Cu was studied. The solution treated alloys containing different amounts of Cu were aged isochronally for 1 hour at temperatures up to 300 o C. The precipitation stages during ageing were monitored by hardness measurements. Tensile and impact properties were determined by standard tests. During artificial ageing, the yield and ultimate tensile strengths were found to increase with ageing temperature; the maximum being attained at peak aged condition. Ductility and impact toughness of the alloys, on the other hand decreased with ageing temperature reaching the minimum at the highest hardness. The addition of Cu resulted in an increase in hardness and tensile strength and substantial reduction of ductility and fracture toughness. Keywords Al-6Si-0.5Mg Alloy, Age hardening, Tensile properties, Fracture toughness, SEM

Highlights

Due to high strength-to weight ratio, besides other desirable properties like appearance, high corrosion resistance, high electrical and thermal conductivities and ease of fabrication, aluminum and its alloys are used in a wide range of industrial applications, in aircraft and space vehicles, construction and building, containers and packaging and in electrical transmission lines [1]
Micro mechanisms governing fracture characteristics of such alloys depend on coherency and distribution of precipitates, grain size and shape, grain boundary precipitates and presence of other second phase particles that result from impurities
This indicates that the fracture was ductile fracture in the Al matrix and brittle in the primary Si particles

Summary

Introduction

Due to high strength-to weight ratio, besides other desirable properties like appearance, high corrosion resistance, high electrical and thermal conductivities and ease of fabrication, aluminum and its alloys are used in a wide range of industrial applications, in aircraft and space vehicles, construction and building, containers and packaging and in electrical transmission lines [1]. Controlled thermo mechanical treatments can induce considerable improvements in yield strength and hardness of age hardenable Al-alloys. Micro mechanisms governing fracture characteristics of such alloys depend on coherency and distribution of precipitates, grain size and shape, grain boundary precipitates and presence of other second phase particles that result from impurities. Fracture characteristics under the impact load seem to become important, because the application to transportation vehicles is likely to increase [2]

Methods

Results

Conclusion