Microstructure and Mechanical Properties of Al–SiC Nanocomposites Synthesized by Surface-Modified Aluminium Powder

Xiang Zeng,Guogang Shu,Wei Liu,Ben Xu,Qiulin Li

doi:10.3390/met8040253

Abstract

Ceramic nanoparticle-reinforced aluminium metal matrix composites (AMMCs) have superior mechanical properties compared with matrix alloys, exhibiting great potential in structural applications in industries such as the aerospace and automotive sectors. This research proposes a new method for distributing SiC nanoparticles in an aluminium matrix alloy by powder metallurgy. The mixing of aluminium powder and SiC nanoparticles was processed by a two-step procedure, which included ultrasound-assisted stirring and planetary agitation. After that, the mixing powder was subjected to compaction, sintering and extrusion. A blank sample and three composite sheets containing 1, 2 and 3 wt % SiC nanoparticles were prepared and the mechanical properties were investigated by micro-hardness and tensile tests. A scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD) were used for microstructural analysis of the composite. Experimental results revealed that by adding 1, 2, 3 wt % SiC nanoparticles, hardness was increased by 26%, 34.5%, 40.0% and tensile strength was increased by 22.3%, 28.6% and 29.3%, respectively. The grain size of the aluminium matrix decreased with the addition of SiC nanoparticles. Moreover, a decrease of elongation was observed with the increasing weight fraction of SiC.

Highlights

With advances in the field of material science, demand for lighter weight and higher strength materials is increasing
Ma et al reported that aluminium composite reinforced by only 1 vol % Si3 N4 (D50 is about 10 nm) had nearly the same tensile strength and even much higher yield strength compared to 15 vol % Silicon carbide (SiC)
A micrograph of composite containing 1 wt % of silicon carbide nanoparticles is shown in Figure 4a, which shows that the SiC nanoparticles adhere to the aluminium particles with a relatively uniform distribution on the surface of the aluminium particles

Summary

Introduction

With advances in the field of material science, demand for lighter weight and higher strength materials is increasing. Metal matrix nanocomposites reinforced with ceramic particles are very promising materials for aerospace, automobile and defense applications due to the excellent combination of properties [1,2,3,4,5,6,7]. Compared to micro-sized ceramic particles, the nanoparticles exhibit a more efficient ability as reinforcement for metal matrix composites [8]. Ma et al reported that aluminium composite reinforced by only 1 vol % Si3 N4 (D50 is about 10 nm) had nearly the same tensile strength and even much higher yield strength compared to 15 vol % SiC Silicon carbide (SiC) and aluminium oxide (Al2 O3 ) nanoparticle-reinforced aluminium metal matrix composites have drawn lots of attention for their economic advantages and better performance. Many methods can be used for fabrication of Al matrix nanocomposites such as infiltration [10], squeeze casting [11], mechanical alloying [12], powder metallurgy [13], ball milling [14]

Methods

Results

Discussion

Conclusion