Role B4C Addition on Microstructure, Mechanical, and Wear Characteristics of Al-20%Mg2Si Hybrid Metal Matrix Composite

Hamidreza Ghandvar,Abdollah Bahador,Mostafa Abbas Jabbar,Tuty Asma Abu Bakar,Michal Petrů,Seyed Saeid Rahimian Koloor,Katsuyoshi Kondoh

doi:10.3390/app11073047

Abstract

In the current study, the effect of different B4C additions (0, 2.5, 5, and 10 wt%) on the microstructural, solidification behavior, mechanical, and tribological properties of Al-20%Mg2Si composite were studied by means of scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Vickers hardness, tensile, and dry sliding wear tests. The cooling curve thermal analysis (CCTA) approach was utilized to monitor the influence of B4C particles on the solidification behavior of Al-20%Mg2Si composite. The results revealed that the addition of B4C particles up to 10 wt% reduced the nucleation temperature (TN) and growth temperature (TG) of the primary Mg2Si phase. Moreover, the proper amount of B4C added to Al-20%Mg2Si composite has a significant effect on the microstructural alteration, mechanical, and tribological properties of the composite. The mean size of primary Mg2Si in Al-Mg2Si composite was 47 μm, in which with the addition of 5 wt% B4C, the particle size decreased to 33 μm. The highest UTS (217 MPa) and El% (7%) was achieved in Al-20%Mg2Si-5%B4C hybrid composite. The cast Al-20%Mg2Si composite revealed the brittle mode of fracture with some cleavage characterization, in which with the addition of 5%B4C, the fracture mode altered to a more ductile fracture. The wear results revealed that the Al-20%Mg2Si-5%B4C hybrid composite has the highest wear resistance with the lowest wear rate (0.46 mm3/Km) and friction coefficient (µ = 0.52) under 20 N applied load compared to other fabricated composites with mild abrasion as the governed wear mechanism.

Highlights

IntroductionThe focus of materials design has moved towards lightweight, low-cost, and environmentally sustainable
In order to fabricate the hybrid composites, Al ingot was melted at 800 ◦ C using an induction furnace, and Si was added to the molten metal at the same temperature
Patterns of Al-20%Mg2 Si-10% boron carbide (B4 C) hybrid composite is illustrated in Figures 1b and 2 respectively, which indicate the existence of the Al, Mg2 Si and B4 C in the hybrid metal matrix composites (HMMCs)

Summary

Introduction

The focus of materials design has moved towards lightweight, low-cost, and environmentally sustainable. According to this trend, aluminum metal matrix composites (AMMCs) have received considerable attention due to their enhanced properties (low density, brilliant cast ability, excellent mechanical properties, and good wear resistance) and low production cost [1]. Mg2 Si, displays high melting temperature (1085 ◦ C), low density (1.99 × 103 kgm−3 ), high elastic modulus (120 GPa), high hardness (4.5 GPa), and a low coefficient of thermal expansion (7.5 × 10−6 K−1 ) [2]. As a result of the outstanding physical and mechanical properties of the Mg2 Si phase, Al-Mg2 Si or Mg-Mg2 Si composites are desirable candidate materials for aerospace, automobile, and other applications [2]

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Conclusion