Given the following stressstrain behaviour of three differen

Given the following stress-strain behaviour of three different materials, which one is the toughest material? Material A Material B Material C which one of the following is the hardest? Course pearline Bainite Fine perlite Martensite Which one of the following is Not the method to strengthen the metal? Form alloys Form solid solutions Enlarge the gain sizes Use cold working process What is the percent cold work(%CW) of a cylindrical copper rod when its diameter is reduced from 10 mm to 8 mm? 20% 36% 55% 64% True/False: Critical resolved shear is a material property.

Solution

1. Toughest material is the one with more area so from the figure we can say that material B is toughest.

2. Martensite is the toughest material.

3. Enlarging grain sizes reduces the strength of metal.

4. %CW =(Intial Area - Final Area)/(Intial Area)

= (10² - 8² )/(10²)

=36%

5. True. Citical resolved shear stress is a material property.

6. False... Higher is the value of safety factor, more safer is the design.