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Microstructure and microhardness of Cu-Al-Mn-Zr alloys before and after heat treatment

In this work preliminary results of the heat treatment effect on microstructure and microhardness of Cu-8.5Al-10Mn-(0.25-1.00)Zr alloys were presented. Ingots (8 mm in diameter and 15 mm in length) were produced by melting and casting process. Production of investigated alloys was performed in laboratory electric arc furnace. Melting was carried out using the heat produced by electric arc and by a water-cooled, specially constructed copper anode that also served as a casting mould. The samples were analysed in as-cast state and after heat treatment at 900 °C/15 min/water. Microstructural analysis was performed by optical microscopy (OM), scanning electron microscopy (SEM) equipped by device for energy dispersive spectroscopy (EDS). Preliminary optical microscopy analysis of investigated alloys confirmed that microstructure was consisted of martensite only in Cu-8.5Al-10Mn- 0.25Zr alloy in as-cast and heat treated state. SEM analysis show the start of martensite formation in some places at all investigated alloys in both, as-cast and heat treated state. A microhardness measurement was performed by Vickers method. Microhardness values of Cu- 8.5Al-10Mn-(0.25-1.00)Zr alloys were up to 215.8 HV1 after casting and up to 224.5 HV1 after heat treatment.

Cu-Al-Mn-Zr alloy, microstructure, heat treatment, microhardness

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