A holistic approach to Thermo-Mechanical Fatigue phase angle effects for an aerospace nickel superalloy

In this work, the initiation and propagation behaviors of naturally initiated small crack in a polycrystalline Ni-base superalloy under the several kinds of thermos-mechanical fatigue (TMF) conditions. The effect of phase angle between temperature and strain cycles in TMF loading on the initiation and propagation behavior of small crack was discussed. The experimental results revealed that the initiation and propagation morphologies of fatigue small crack were affected on the phase angle; the crack initiation mode was changed from the intergranular mode to the transgranular mode with the increasing of the phase angle in this study. On the other hand, when the crack growth rates of naturally initiated small crack are correlated with fatigue J-integral range, the effect of the phase angle on the small crack growth rates became negligible even if the crack propagation mode depended on it.

Download Full-text

Influence of phase angle on lifetime, cyclic deformation and damage behavior of Mar-M247 LC under thermo-mechanical fatigue

Materials Science and Engineering A ◽

10.1016/j.msea.2015.06.055 ◽

2015 ◽

Vol 642 ◽

pp. 42-48 ◽

Cited By ~ 9

Author(s):

Stefan Guth ◽

Simon Doll ◽

Karl-Heinz Lang

Keyword(s):

Phase Angle ◽

Cyclic Deformation ◽

Damage Behavior ◽

Mechanical Fatigue

Download Full-text

Influence of Aluminide Coating on Fatigue Behavior of a Nickel Superalloy

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Process Industries; Technology Resources; General ◽

10.1115/85-igt-77 ◽

1985 ◽

Author(s):

Xu Jianping ◽

Xiong Jiyuan

Keyword(s):

Surface Roughness ◽

Fatigue Behavior ◽

Aluminide Coating ◽

Alloy System ◽

Nickel Superalloy ◽

Metal Fatigue ◽

Mechanical Fatigue ◽

Substrate Alloy ◽

Coating Alloy ◽

Coating Crack

The influence of the technology and the thickness of an aluminide coating on mechanical fatigue of a nickel-alloy at 700°C has been studied. It was shown that the brittleness and the surface roughness of coating were the basic causes to the earlier rupture of a system. The thicker coating, the more harmful to fatigue performance. The mechanism of influnece of coating on metal fatigue and the possibility to estimate fatigue life of coating/alloy system were also discussed. It is believed that the stress concentration caused by coating crack accelerated substrate alloy to rupture.

Download Full-text