Role of Gd addition on machinability of Al-15%Mg2Si in-situ composite during dry turning

Is Prima Nanda,Auliya Hanif,Hamidreza Ghandvar,Mohd Hasbullah Idris,Andril Arafat

doi:10.21924/cst.5.2.2020.186

Abstract

Recently, Al-Mg2Si in-situ composites have achieved considerable attention due to their excellent physical and mechanical properties. In fact, there are some limitations of knowledge regarding the machinability characteristics of these composites - particularly when being inoculated with rare earth additions. This study in turn aimed to investigate the influence of machining parameters as well as Gd addition on the machinability of Al-15%Mg2Si composite. To examine the effect of modifier (1.0 wt. % Gd) and machining parameters (feed rate, cutting speed), microstructural evolution, surface roughness (Ra) and cutting force (Fc) were evaluated during dry turning. The results revealed that Gd addition as modifier element led to better surface roughness and higher cutting force owning to the modification of Mg2Si particle structure as well as the formation of Gd intermetallic compounds.

Highlights

In-situ fabrication of the particulate metal matrix composites (PMMCs) during casting has some advantages such as simple production during solidification, good reinforcement particles distribution, excellent particle wetting and thermodynamic stability of particles compared to ex-situ technique [1,2].In-situ MMCs have gained considerable attention due to the convenient technical process and strong interface between reinforcement and matrix [3]
Composite modification using Gd addition led to the increase in density to 1167 particle/mm2 and reduction in aspect ratio and size to 1.25 and 20μm respectively
The results indicated the increase of feed rate from 0.1 mm/rev to 0.2 mm/rev and the increase of the main cutting force in all conducted tests owning to the load increasing on tool tip as well as the existence of high friction between tool rake surface

Summary

Introduction

In-situ fabrication of the particulate metal matrix composites (PMMCs) during casting has some advantages such as simple production during solidification, good reinforcement particles distribution, excellent particle wetting and thermodynamic stability of particles compared to ex-situ technique [1,2].In-situ MMCs have gained considerable attention due to the convenient technical process and strong interface between reinforcement and matrix [3]. The tensile properties and machinability of hypereutectic Al-Mg2Si in-situ composite are determined by the morphology and size of Mg2Si particles; controlling the structure of Mg2Si particles is deemed crucial to achieve the superb mechanical and machinability properties [6,7,8] In this respect, several approaches such as rapid solidification [9], hot extrusion [10] and superheat treatment [11] and the addition of modifying elements such as Gd [12], Bi [13], Ba [14] and Sb [15] have been applied to control the microstructure of Al-Mg2Si composite.

Methods

Results

Conclusion