Effect of phase angle on the cyclic behavior of AISI 410 alloy

Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia;

^* nesar@kfupm.edu.sa

Abstract

Multiaxial strain-controlled fatigue tests were conducted on AISI 410 according to ASTM 2207-E08 [1] under proportional (phase angle, θ = 90°) and non-proportional (phase angle, θ = 90º) loadings. Axial strain amplitudes in the range of 0.2%-0.35% are paired with shear strain amplitudes in the range of 0.25%-0.5%. Comparison was made between the hysteresis loops under both loading modes. It was found that peak stresses are higher under nonproportional loading, but with less plastic deformation. Additional stress hardening is exhibited by the alloy, resulting in the tip of the hysteresis loop under nonproportional loading to be rounded. Stress evolution with the number of fatigue cycles, mainly show cyclic stress softening except in axial stress under nonproportional loading where stress stabilization is largely the case after initial hardening. Fatigue life under nonproportional loading is generally lower than that of proportional loading.