INFLUENCE OF TERNARY ALUMINIUM AND QUATERNARY ZIRCONIUM ON THE PHYSICAL PROPERTIES OF BELL METAL

Authors : Maglub Al Nur, Sakıb Al Razı Khan, Mohammad Ashfaq Hossain, Mohammad Kaiser

Pages : 75-89

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Publication Date : 2020-12-31

Article Type : Research

Abstract :The change in physical properties of bell metal due to ternary addition of Al and quaternary addition of Zr has been reported. Cast samples are aged both isochronally and isothermally. Investigation on the age hardening property reveals that due to the formation of intermetallic precipitates, significant hardening takes place in case of Al added alloys and Zr addition enhances the thermal stability of the alloy. The comparative acoustic response study discloses that heat-treatment improves the sound quality of all three bell metal alloys. The base alloy shows highest decibel values for differently aged temperatures. The ternary Al added alloy and quaternary Zr added alloy show continuous increase in decibel values with increasing ageing temperature. However, the acoustic response curve of the alloys almost followed the similar pattern of hardness curve with the ageing temperature. Spectral reflectance study reveals that the ternary Al added alloy shows better percent reflectance with the increase of wavelength of incident light. The quaternary Zr added alloy is also seen to retain its superior optical properties for all ageing conditions. It is found from microstructural analysis that ternary Al addition creates a new microstructure with relatively large dendritic arms and the quaternary addition of Zr refines the grain structure. The base alloy attained almost full recrystallization state after ageing at 300°C for 60 minutes while the ternary Al added alloy was also recrystallized at elevated temperature of 500°C but the quaternary Zr added alloy did not attain recrystallization and maintained its grain structure due to thermal stability.
Keywords : Bell metal, Age hardening, Sound level, Reflectance, Microstructure