Process-Structure-Property Relationships of Copper Parts Manufactured by Laser Powder Bed Fusion.

Mohamed Abdelhafiz,Kassim S Al-Rubaie,Mohamed A Elbestawi,Ali Emadi

doi:10.3390/ma14112945

Abstract

The process–structure–property relationships of copper laser powder bed fusion (L-PBF)-produced parts made of high purity copper powder (99.9 wt %) are examined in this work. A nominal laser beam diameter of 100 μm with a continuous wavelength of 1080 nm was employed. A wide range of process parameters was considered in this study, including five levels of laser power in the range of 200 to 370 W, nine levels of scanning speed from 200 to 700 mm/s, six levels of hatch spacing from 50 to 150 μm, and two layer thickness values of 30 μm and 40 μm. The influence of preheating was also investigated. A maximum relative density of 96% was obtained at a laser power of 370 W, scanning speed of 500 mm/s, and hatch spacing of 100 μm. The results illustrated the significant influence of some parameters such as laser power and hatch spacing on the part quality. In addition, surface integrity was evaluated by surface roughness measurements, where the optimum Ra was measured at 8 μm ± 0.5 μm. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) were performed on the as-built samples to assess the impact of impurities on the L-PBF part characteristics. The highest electrical conductivity recorded for the optimum density-low contaminated coils was 81% IACS.

Highlights

Laser powder bed fusion (L-PBF), known as selective laser melting (SLM), is one of the main metal additive manufacturing (AM) methods used for producing parts with complicated geometries
The electrical conductivity (EC) scale of all metals is expressed as a percent of the international annealed copper standard (IACS); i.e., 100% IACS is equivalent to 58 × 106 S/m for C10700 and C11300 copper alloy
Substituting with the thermophysical properties of Cu powder [24] yields Et of 4.8 J/mm3, Ev should be equal to or greater than this value to ensure that the laser energy can raise the Cu powder temperature to the melting point

Summary

Introduction

Laser powder bed fusion (L-PBF), known as selective laser melting (SLM), is one of the main metal additive manufacturing (AM) methods used for producing parts with complicated geometries. Pure copper has the best electrical conductivity (EC) amongst nonprecious metals. The EC scale of all metals is expressed as a percent of the international annealed copper standard (IACS); i.e., 100% IACS is equivalent to 58 × 106 S/m for C10700 and C11300 copper alloy. Franz relationship [1], thermal conductivity (TC) is strongly proportional to EC, making copper an excellent candidate for most electrical and thermal management applications. Significant research efforts were aimed at AM of copper alloys for electrical and thermal applications. These efforts were the result of the need for more effective and compact designs of electrical drives in the automotive industry

Methods

Results

Conclusion