Solid-state transformations refer to changes in the structure of a solid material without it becoming a liquid. These transformations can occur due to variations in temperature, pressure, or composition, leading to different phases or microstructures. Common examples include the transition of iron to austenite when heated, which alters its properties. These transformations are crucial in materials science, as they affect the mechanical, electrical, and thermal properties of materials. Understanding solid-state transformations helps in the development of new materials and improving existing ones, such as in the production of steel or semiconductors.