Bonding SiCp/Al Composites via Laser-Induced Exothermic Reactions

Yifeng Wang,Dean Deng,Bingxu Hu,Yan Wei,Guangjie Feng

doi:10.3390/cryst11050535

Abstract

In this paper, the SiCp/Al composites were bonded via laser-induced exothermic reactions of a Ni–Al–Zr interlayer. The Ni–Al–Zr interlayer was designed based on its exothermic property and chemical compatibility with the SiCp/Al composites. The influences of the interlayer composition and bonding pressure on the joint microstructure and shear strength were investigated. Results indicated that high exothermic reactions occurred in the Ni–Al–Zr interlayer and realized the reliable bonding with the SiCp/Al composites. The interlayer products were the eutectic structure of NiAl+Ni2AlZr+Ni3Al5Zr2. NiAl3 and Ni2Al3 reaction layers were formed at the bonding interfaces. The interlayer composition and the bonding pressure determined the morphology and distribution of the voids and the reaction layers, thus controlling the joint shear strength. When the SiCp/Al composites were bonded using the interlayer with the Zr content of 15 wt.% under the bonding pressure of 3 MPa, the joint shear strength reached the maximum of 24 MPa.

Highlights

Particle-reinforced aluminum matrix composites, such as SiCp/Al composites [1], Si3N4/Al composites [2], SiO2/Al composites [3], Al2O3/Al composites [4], B4C/Al composites [5], and TiC/Al composites [6], process excellent electrical and chemical properties, as well as the comprehensive mechanical performances, and have been important structural materials in aerospace, electronics, and automobile industries
Due to the SiC particles with high hardness, machining is not suitable for the SiCp/Al composites [10]. One solution for this issue is that the component with complex structure can be manufactured through bonding modular SiCp/Al composite pieces together
When the bonding pressure was 3 MPa, there were only some small voids distributed around the bonding interfaces

Summary

Introduction

Particle-reinforced aluminum matrix composites, such as SiCp/Al composites [1], Si3N4/Al composites [2], SiO2/Al composites [3], Al2O3/Al composites [4], B4C/Al composites [5], and TiC/Al composites [6], process excellent electrical and chemical properties, as well as the comprehensive mechanical performances, and have been important structural materials in aerospace, electronics, and automobile industries. At high temperature, harmful interfacial reactions will occur between the SiC particles and aluminum matrix, forming a large quantity of brittle Al4C3 compounds and resulting in the degeneration of mechanical properties. Compared with conventional welding techniques, such as fusion welding [13], brazing [14,15], diffusion bonding [16], etc., the exothermic bonding has some inherent advantages on the bonding of SiCp/Al composites It utilizes the exothermic reactions in the interlayer as the heat source to enhance the atomic activities and promote the metallurgical reactions at the bonding interface [17]. The transient high temperature could significantly increase the chemical activity of SiC particles at the bonding interface and enhance the metallurgical reactions with the filler metals, and avoid the harmful thermal damage on the substrates. The influences of the bonding parameters on the microstructural evolution and mechanical property of the joint were investigated systematically

Experimental Procedures

Results and Discussion

Influence of the Interlayer Chemical Composition on the Joint Microstructure

Influence of the Bonding Pressure on the Joint Microstructure

Joint Shear Strength

Conclusions