Draw a stress-strain curve for a low carbon steel and explain important points and regions in detail. What fracture behavior does this steel exhibit?

Specify a copper alloy that requires at least 50% elongation and at least 300 MPa tensile strength.

A component made of 7075-T6 aluminum alloy has an edge crack of 1.4 mm in length. Plane strain fracture toughness of this alloy is given as 27 MPavm. Geometrical factor of the crack is given as 1.2. (a) If this alloy is subjected to uniaxial tensile stress of 380 MPa, determine whether sudden brittle fracture occurs or not. (b) Calculate the maximum allowable crack size for this component in order not to be failed in brittle manner under a stress of 1000 MPa (Density of steel 7.85 g/cm³, 9.80665 N = 1 kg). Modulus of elastisity, GPa Ultimate tensile Yield strength, Alloy strength, MPa MPa 2014 Al alloy Bronze (92Cu-8Sn) High carbon steel Pure Titanium 97 186 380 72 110 152 380 615 215 240 330 107

(a) A large medium carbon steel crane hook is thought to contain penny- shaped internal cracks. If the non-destructive test equipment used on the hook is not capable of detecting cracks smaller than 20 mm diameter, determine the fracture toughness required from this steel if the safety factor on stress is to be 2. The yield stress of the AISI 1045 grade steel is 1050 MNm². Note: For this crack geometry, the 'compliance function' Y in the Stress Intensity Factor (K)) may be taken as 1. (b) A surface crack of 2.5 mm depth and a certain length is found in a thick rectangularcomponent. The component is schedule to be repaired in 6 months. The component is subjected to zero to maximum stress of 340 MPa, 50 times per hour. It was known that for this component catastrophic failure occurs when the crack size reaches 12 mm in depth. Assuming that the crack geometrical shape (aspect ratio) remains constant during crack growth, will the component fail before repair? For the crack geometry, the…