International Journal of Science, Engineering and TechnologyAuthors: Associate Professor Rajesh Kant
Abstract: The present work examines the relationship between anisotropic growth velocity and the mechanical behaviour of the Pb–Sn–Cd eutectic composite. The alloy was prepared from the constituent metals using the heat-chill method and its eutectic melting point was determined by differential scanning calorimetry. The composition investigated was Sn 51.2 wt%, Pb 30.6 wt%, Cd 18.2 wt%, with a measured eutectic melting point of 418.2 K. Macrohardness-related strength modes and Vickers microhardness were evaluated as functions of growth velocity, indentation time and applied load. At approximately 3.1 × 10⁻⁷ m s⁻¹, the modulus of rupture is 50.70 × 10⁵ N m⁻², tensile strength is 61.80 × 10⁴ N m⁻² and compressive strength is 64.20 × 10⁴ N m⁻². Microhardness rises from 17.60 kg mm⁻² at 0.50 × 10⁻⁷ m s⁻¹ to a maximum of 37.60 kg mm⁻² at 3.10 × 10⁻⁷ m s⁻¹ and then decreases to 17.80 kg mm⁻² at 7.50 × 10⁻⁷ m s⁻¹. At a 20 g load, microhardness remains nearly constant with indentation time, ranging approximately from 36.10 to 36.70 kg mm⁻² over 20–150 s. With indentation load, Hv decreases from 39.50 kg mm⁻² at 10 g to 18.10 kg mm⁻² at 100 g. The results demonstrate a characteristic optimum or moderate-growth region in which the fibrous eutectic microstructure and mechanical response are maximized. The observations support the interpretation that directional/fibrillar growth produces stronger, more coherent microstructures than instantaneous or very rapid growth.
