Induction melting of an Al-50Cu alloy for improved homogeneity required for powder spheroidisation

R van der Merwe; H Bissett; I J Van Der Walt; L A Cornish

R van der Merwe The South African Nuclear Energy Corporation SOC Ltd.
H Bissett The South African Nuclear Energy Corporation SOC Ltd.
I J Van Der Walt The South African Nuclear Energy Corporation SOC Ltd.
L A Cornish University of the Witwatersrand

Keywords: Cu-Al button, Induction melting, homogeneity, spheroidisation

Abstract

Copper alloys are typically produced by conventional casting processes, including spark plasma sintering (SPS), which often produce inhomogeneous mixtures of Cu or Al precipitates and unwanted intermetallic phases in solid products. Induction melting should provide good mixing, controlled heating and melt stirring, potentially improving homogeneity. Homogeneous melts should produce homogeneous powders, giving better properties in additive manufacturing (AM). To ascertain homogeneity, a density test was developed. After comminution, homogeneous powders can be used to produce high quality components. To manufacture dense AM components, spheroidised powders are needed because they increase particle packing and powder flow. An Al-50Cu (at.%) button was produced by high-frequency (HF) induction melting, to give better mixing and hence phase distributions. To identify the phases and their distributions, the as-cast sample was studied using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD), as well as absolute density using helium pycnometry. Results indicated inhomogeneity in the samples, due to Al loss, complex solidification and the densest phase settling at the bottom of the button.

Author Biographies

R van der Merwe, The South African Nuclear Energy Corporation SOC Ltd.

The South African Nuclear Energy Corporation SOC Ltd. (Necsa), Elias Motsoaledi Street Extension (Church Street West) R104 Pelindaba, Madibeng Municipality, North West Province, 0240, South Africa

H Bissett, The South African Nuclear Energy Corporation SOC Ltd.

The South African Nuclear Energy Corporation SOC Ltd. (Necsa), Elias Motsoaledi Street Extension (Church Street West) R104 Pelindaba, Madibeng Municipality, North West Province, 0240, South Africa

I J Van Der Walt, The South African Nuclear Energy Corporation SOC Ltd.

The South African Nuclear Energy Corporation SOC Ltd. (Necsa), Elias Motsoaledi Street Extension (Church Street West) R104 Pelindaba, Madibeng Municipality, North West Province, 0240, South Africa

L A Cornish, University of the Witwatersrand

School of Chemical and Metallurgical Engineering, and DSI-NRF Centre of Excellence in Strong Materials hosted by the University of the Witwatersrand, Johannesburg, South Africa

Induction melting of an Al-50Cu alloy for improved homogeneity required for powder spheroidisation

Abstract

Author Biographies

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