Which of these measures may be taken to increase the resista

Which of these measures may be taken to increase the resistance to fatigue of a metal alloy. Polish the surface to remove stress amplification sites. Reduce the number of internal defects (pores, etc.) by means of altering processing and fabrication techniques Modify the design to eliminate notches and sudden contour changes. Harden the outer surface of the structure by case hardening (carburizing, nitriding) or shot peening. All of the above

Solution

Fatigue failure is the ability of material to a fracture by means of brittle cracking under repetitive stress.

Fatigue strength can be improved by polishing the surface which remove stress intesifier sites, reducing internal defects, by eliminating notches and sudden contour changes, and by means of hardening (surface and case).

Therefore, correct option is (e) All of the above