International Journal of Science, Engineering and TechnologyAuthors: Associate Professor Rajesh Kant
Abstract: The mechanical response of the Pb–Cd binary eutectic composite (36 wt% Pb – 64 wt% Cd) was systematically investigated as a function of solidification mode and growth velocity. Differential scanning calorimetry (DSC) confirmed a eutectic melting temperature of 513.2 K. Rod-like eutectic specimens were prepared via anisotropic directional growth, alongside rapidly solidified samples prepared by ice-bath quenching. Macrohardness was evaluated through modulus of rupture, tensile strength, and compressive strength, while local microhardness was characterized using the Vickers indentation technique. Mechanical properties exhibited a pronounced non-monotonic dependence on growth velocity: strength and hardness increased from the slow-growth region to an optimal moderate-growth velocity near 3.19 × 10⁻⁷ m s⁻¹, followed by a marked decrease in the fast-growth region. At the optimal growth velocity, the modulus of rupture, tensile strength, and compressive strength reached maximum values of 60.5 × 10⁵ N m⁻², 66.22 × 10⁴ N m⁻², and 72.2 × 10⁴ N m⁻², respectively. Vickers microhardness at 20 g load increased from 18.2 kg mm⁻² at 0.50 × 10⁻⁷ m s⁻¹ to a peak of 38.6 kg mm⁻² at 3.10 × 10⁻⁷ m s⁻¹. These results demonstrate that the directional alignment and refined scale of the fibrillar/lamellar microstructures developed during moderate-velocity growth yield optimal mechanical performance.
