Mechanical and Microstructural Characterization of Hybrid Cu-SiC-Zn Composites Fabricated Via Friction Stir Processing

Mohsen Barmouz,Vahid Zall,Hamed Pashazadeh

doi:10.1590/1980-5373-mr-2016-0152

Abstract

In this work, an attempt has been made to fabricate hybrid Cu-SiC-Zn composites by friction stir processing technique. Through this investigation the different number of passes was applied to assess the effect of pass adding on the mechanical, microstructural and dislocation density behavior of the specimens. Formation of the intermetallic phases between the copper matrix and Zn particles was discovered through the processed specimens. According to the obtained results, the higher passes led to obtain more uniform dispersion of the SiC particles and intermetallic phases. This higher level of particles and intermetallic phases' distribution causes remarkable reduction of grain sizes through the composites. Dislocation density for the processed specimens was determined by using the hardness measurement method. The calculated values for the dislocation densities showed that presence of SiC particles and intermetallic phases could rise up the dislocation values. Measured microhardness values for the composites exhibit that they enhanced rather than base metal and these results were confirmed by dislocation densities values of the specimens.

Highlights

Due to special mechanical and thermal properties of intermetallic materials, researchers and industries have become interested in these materials in the recent years
It is clear in the EDX results that with increase of Friction stir processing (FSP) passes, the volume fraction of copper tend to be lessened in the regions revealing the fact that higher level of SiC and Zn distribution inside the matrix has been obtained
There are some valuable reports on the field of hardness indentation size effect to estimate the dislocation densities which are confirmed by transmission electron microscopy (TEM) results

Summary

Introduction

Due to special mechanical and thermal properties of intermetallic materials, researchers and industries have become interested in these materials in the recent years. Asadi et al.[9,10] produced AZ91/SiC and AZ91/Al2O3 composites and nanocomposites by using FSP and examined the effects of passes number, rotational and traverse speeds on the quality of the achieved products They concluded that in the higher passes number, the reinforcing particles are distributed uniformly, grains get finer and micro hardness of the products increases significantly. Barmouz et al produced copper base composites reinforced with SiC micro particles via FSP to increase surface property of the copper Addition of zinc particles in copper/ SiC composites can create copper/zinc intermetallic phases and increase wettability of copper matrix with SiC particles To achieve these composites and intermetallic with specific mechanical and metallurgical properties, in this work, ball-milled SiC particles and zinc powders were added into a copper matrix by using the FSP method. XRD scans were performed on the cross-sections of the specimens and perpendicular to the FSP direction

Results and Discussions

Microstructure

Dislocation density determination

Microhardness behavior

Conclusion