(a) Ductile Cast Iron:
Ductile cast iron is a type of cast iron with improved ductility and toughness compared to traditional cast iron. This is achieved by adding a small amount of magnesium or cerium during the manufacturing process, which changes the graphite microstructure from flakes to spheroids. This results in a material that can deform considerably before breaking, unlike the brittle nature of traditional cast iron. Ductile cast iron is used in various applications like pipes, automotive components, and machine parts requiring strength and some flexibility.
(b) Tensile Stress:
Tensile stress is a pulling force acting on a material, trying to elongate it in the direction of the force. Imagine pulling a rope: the rope experiences tensile stress, stretching as you pull harder. It is one of the basic types of stress encountered in materials, alongside compressive stress (pushing) and shear stress (distortion).
(c) Work Hardening:
Work hardening, also known as strain hardening, is a phenomenon where a material’s strength and hardness increase as it undergoes plastic deformation (permanent shape change) due to external forces. Imagine repeatedly bending a metal wire: it becomes progressively harder to bend further as the work hardens. This property is utilized in metalworking processes like cold forging and wire drawing.
(d) Shear Stress:
Shear stress is a force that acts to slide or distort one part of a material relative to another along a parallel plane. Picture pushing two bricks against each other: they experience shear stress at the contact point, potentially causing them to slide and deform. It is another fundamental type of stress alongside tensile and compressive stress, and it plays a crucial role in phenomena like friction and material failure.
(e) Young’s Modulus:
Young’s modulus, also known as the elastic modulus, measures the stiffness of a material within its elastic range (where deformation is temporary). It quantifies the relationship between stress and strain within this region. A higher Young’s modulus indicates a stiffer material that requires more force to deform a given amount. Think of a steel beam compared to a rubber band: the steel has a much higher Young’s modulus, making it much stiffer.