Study of the low cyclic behaviour of the IRIS alloy at high temperature

Abstract

This paper presents experimental results on low cycle fatigue (LCF) behaviour at high temperatures of the IRIS alloy (Ti-Al48-W2-B0.08, at. %) densified by Spark Plasma Sintering (SPS). Cyclic stability is noticed, whatever the temperature and the total strain amplitude. Fracture occurs by mixed interlamellar and translamellar modes. Transmission electron microscopy (TEM) observations reveal that deformation is mainly due to ordinary dislocations and twins, and slip and cross-slip mechanisms have been clearly evidenced, without significant contribution of climb at 800°C. It has also been established that dislocation density depends on fatigue life time rather than on stress amplitude.

Elaboration of Metallic Materials by SPS: Processing, Microstructures, Properties, and Shaping

“…Sintering of metallic disks up to 350 mm in diameter has been reported [93], but a limited number of studies have been published to date. Early works report on processing of large specimens constituted of the following materials: Al [94], Ti (Figure 16) [95], TiAl [74,96]. One of the main difficulties, when processing parts of large dimensions is the presence of thermal and hence microstructure gradients in the materials, which are amplified with respect to those existing in small size samples.…”