In-situ Study of the Mechanisms of High Temperature Damage in Elastic-plastic Cyclic Loading of Nickel Superalloy

conference paper

English

In-situ Low Cycle Fatigue test (LCF) at temperature 635 C have been performed in SEM on flat specimen of cast Inconel 713LC superalloy. The aim of the investigation was to study mechanisms of the fatigue damage during elastic-plastic cycling by the observations of the characteristic surface relief evolution and the accompanying internal dislocation structures. The selected locations on the surface were systematically studied in-situ and documented by SEM and using AFM. The surface relief in the first tensile half-cycle was formed by numerous slip steps on the primary slip planes (111). In the following compression half-cycle additional opposite slip were formed. The relief was modified in the next cycles but without forming additionally new slip traces in the primary system. The reorientation of two grains in the gauge area was measured using EBSD. At the end of cyclic loading the relation between surface persistent slip markings and persistent slip bands in the interior of the material was documented by TEM on lamella prepared by FIB. The early stages of extrusion and intrusion formation were documented. The damage mechanism evolution is closely connected with the cyclic strain localization to the persistent slip bands that are also places of fatigue crack initiation.

fatigue damage; high temperature; nickel superalloy; TEM lamella

PETRENEC, M.; POLÁK, J.; ŠAMOŘIL, T.; DLUHOŠ, J.; OBRTLÍK, K.

2014

1. 3. 2014

978-3-03835-008-8

11th International Fatigue Congress

1662-8985

Advanced Materials Research (online)

891-892

1

Swiss Confederation

530

535

6