Page 99 - eBook_Proceedings of the International Conference on Digital Manufacturing V2

Fabrication and Characterization of a Low-Cost Piezoelectric using Rochelle
Salt for Energy Harvesting and Sensor Applications

Figure 36: Microstructures observed at various pouring
temperatures and holding times: (a) 685 °C, 60s; (b) 685°C, 40s; (c)
685°C, 60s; (d) 665°C, 60s; (e) 665°C, 40s; and (f) 665°C , 20s
(Ahmad, Naher & Brabazon, 2014).

The DTM shows great potential in SSMP, enabling the
formation of spherical microstructures by adjusting processing
parameters during solidification. By retaining a low superheat
alloy in a high-conductivity cylindrical copper mould, DTM
facilitates the development of globular microstructures (Ahmad,
Naher & Brabazon, 2014; Nafisi, Szpunar, Vali & Ghomashchi,
2007; Razak, Ahmad, Rashidi & Naher, 2021). This technique
was further investigated by examining the microstructural
evolution of Aluminium 6061 alloy. The motivation behind this
study lies in addressing common casting defects, such as porosity
and shrinkage, which adversely affect the mechanical properties
of components produced through conventional casting methods.
The DTM aims to generate feedstock billets with refined,
spheroidal grains that are well-suited for thixoforming
applications.

In order to bridge existing knowledge gaps, this study explores
the influence of varying pouring temperatures and holding times
on the microstructure of 6061 alloy billets. Specifically, two
pouring temperatures (660 °C and 680°C) and three holding

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