Final answer:
Tensile strength is the amount of stress before the fracture of an alloy occurs, marking the point of permanent deformation or fracture.
Step-by-step explanation:
The amount of stress before the fracture of an alloy occurs is tensile strength, which is the breaking stress that will cause permanent deformation or fracture of a material. When a material is subjected to stress, it undergoes various stages. Initially, the material shows elastic behavior, meaning it will return to its original shape when the applied stress is removed. If the stress continues to increase, the material reaches its yield strength, after which it will deform plastically. Finally, as stress increases to the ultimate level, the material reaches its tensile strength point, and fracture occurs. Examples of this can be seen in metals like aluminum and steel, which have ultimate stresses of 2.2 × 108 Pa and up to 20.0 × 108 Pa respectively, indicating their tensile strength before breaking. For ductile materials, such as metals, there is a gradual decrease in stress with increasing strain up to the breaking point. Conversely, for brittle materials like bones, the elastic region is small and the fracture is abrupt.