An aluminum alloy used for load bearing construction has a f

An aluminum alloy used for load bearing construction has a fracture toughness of 40 MPa Vw. It has been determined that fracture results at a stress of 300 MPa when the maximum (or critical) internal crack length (2a) is 4.0 mm. For this same component and alloy, will fracture occur at a stress level of 260 MPa when the maximum internal crack length is 6.0 mm? Why or why not?

Solution

The phase diagram represents eutectoid alloy A + B having maximum terminal solid solutions w_alpha = 4.9 wt%A and w_beta =97.5 wt%A. A 100 gram sample of hyper eutectoid alloy composed of A+B, is slowly cooled from the fully gamma phase to room temperature. Analysis determines the sample contains 26 grams of the terminal phase in the pro- form and 17 grams of the terminal phase in the eutectoid form. Determine the wE, eutectoid composition, in wt%A.