Cyclic behaviour of Distaloy AE powder metallurgy steel with superimposed tensile mean stress

Abstract

In the present work, Distaloy AE powder metallurgy (PM) steel, in as-sintered state are experienced under uniaxial fatigue tests in a range of tensile mean stresses. Microstructural investigations reveal that for tensile mean stress, pores are widened and easily linked up by cracks. Moreover, with obtained fatigue results, well-known fatigue failure criteria, such as Goodman, Gerber and Morrow, are employed to the experimental data. The result shows that the experimental data for Distaloy AE porous sintered steel are well suited to these criteria especially in the case of Morrow and Gerber failure criteria. Furthermore, the alteration of samples length versus cycles shows the cyclic hardening behaviour for this diffusion-bonded PM steel. It seems that this concept is a reason for increasing the fatigue property of diffusion-bonded steels in comparison with other PM Steels.

Keywords:

• Powder metallurgy
• Fatigue
• Mean stress
• Cyclic hardening

The authors wish to thank material research centre of SAPCO (Tehran-Iran) for cooperating and providing the experimental facilities. One of the authors (H. Abdoos) wishes to express his special thanks for helpful information provided by Dr D. Whittaker, Dr A. Bergmark and A. Zafari from EPMA (UK), Hoganas AB (Sweden) and IWM (Aachen, Germany), respectively.