skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Localized cyclic plastic deformation on translamellar fracture surfaces in a P/M {gamma}-TiAl-based alloy

Abstract

Large numbers of fine parallel steps are generated on translamellar fracture surfaces during slow crack growth (da/dN {le} 5.0 {times} 10{sup {minus}6} mm/cycle) under cyclic loading. These are seen only rarely during fast crack growth (da/dN {ge} 10{sup {minus}4} mm/cycle) and are not seen during catastrophic fracture. These steps occur due to intense plastic deformation as a result of cleavage on {l_brace}111{r_brace} planes along twin boundaries and dislocation bands. Such action may promote an inherent resistance to crack growth owing to higher energy dissipation. TEM examinations show that the intense deformation structure consists of both microtwins and dislocation bands if the lamellae are orientated to allow easy glide. Conversely, microtwin activity dominates when easy dislocation glide is prevented. Crack initiation and growth resistance are sensitive to such microscopic features within the deformation zone. Lamellar volume fraction, the proportion and distribution of {gamma} grains inside lamellae and lamellar interfacial strength may all influence the local plastic deformation through their interaction with underlying slip and twinning processes.

Authors:
;  [1]
  1. Univ. of Birmingham, Edgbaston (United Kingdom)
Publication Date:
OSTI Identifier:
684379
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 47; Journal Issue: 11; Other Information: PBD: 8 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; FATIGUE; PLASTICITY; TITANIUM ALLOYS; ALUMINIUM ALLOYS; CRACK PROPAGATION; TWINNING; DISLOCATIONS; LAMELLAE; FRACTOGRAPHY

Citation Formats

Huang, Z.W., and Bowen, P. Localized cyclic plastic deformation on translamellar fracture surfaces in a P/M {gamma}-TiAl-based alloy. United States: N. p., 1999. Web. doi:10.1016/S1359-6454(99)00184-6.
Huang, Z.W., & Bowen, P. Localized cyclic plastic deformation on translamellar fracture surfaces in a P/M {gamma}-TiAl-based alloy. United States. doi:10.1016/S1359-6454(99)00184-6.
Huang, Z.W., and Bowen, P. Wed . "Localized cyclic plastic deformation on translamellar fracture surfaces in a P/M {gamma}-TiAl-based alloy". United States. doi:10.1016/S1359-6454(99)00184-6.
@article{osti_684379,
title = {Localized cyclic plastic deformation on translamellar fracture surfaces in a P/M {gamma}-TiAl-based alloy},
author = {Huang, Z.W. and Bowen, P.},
abstractNote = {Large numbers of fine parallel steps are generated on translamellar fracture surfaces during slow crack growth (da/dN {le} 5.0 {times} 10{sup {minus}6} mm/cycle) under cyclic loading. These are seen only rarely during fast crack growth (da/dN {ge} 10{sup {minus}4} mm/cycle) and are not seen during catastrophic fracture. These steps occur due to intense plastic deformation as a result of cleavage on {l_brace}111{r_brace} planes along twin boundaries and dislocation bands. Such action may promote an inherent resistance to crack growth owing to higher energy dissipation. TEM examinations show that the intense deformation structure consists of both microtwins and dislocation bands if the lamellae are orientated to allow easy glide. Conversely, microtwin activity dominates when easy dislocation glide is prevented. Crack initiation and growth resistance are sensitive to such microscopic features within the deformation zone. Lamellar volume fraction, the proportion and distribution of {gamma} grains inside lamellae and lamellar interfacial strength may all influence the local plastic deformation through their interaction with underlying slip and twinning processes.},
doi = {10.1016/S1359-6454(99)00184-6},
journal = {Acta Materialia},
number = 11,
volume = 47,
place = {United States},
year = {1999},
month = {9}
}