TY - JOUR

T1 - Influence of grain aspect-ratio on the fracture properties of ultrafine-grained tantalum

AU - Hohenwarter, Anton

AU - Rockenschaub, Martin

AU - Renk, Oliver

N1 - Publisher Copyright: © 2022 The Author(s)

PY - 2022/4

Y1 - 2022/4

N2 - The fracture characteristics of severely plastically deformed (SPD) materials exhibit large variations in the quasi-static fracture resistance depending on factors such as the investigated material, testing temperature and grain aspect ratio. Especially the latter one is considered to control the frequently observed orientation dependent fracture toughness. A question that arises thereby is how the fracture properties for certain testing directions could be actively tuned by tailoring the grain aspect ratio. In this contribution this issue has been investigated by changing the aspect ratio of ultrafine-grained tantalum processed by high pressure torsion through post-rolling operations which induced a substantial increase of the grain length while keeping the strength on a comparable level. Samples in interesting testing directions were manufactured and tested. The increase of the aspect ratio results in the technically significant testing directions to an enhancement of the fracture toughness. Delamination toughening, which is promoted by the change of the aspect-ratio, has been indentified to be the main cause for the toughness enhancement and represents therefore a feasible pathway for optimizing the damage tolerance of SPD-processed materials.

AB - The fracture characteristics of severely plastically deformed (SPD) materials exhibit large variations in the quasi-static fracture resistance depending on factors such as the investigated material, testing temperature and grain aspect ratio. Especially the latter one is considered to control the frequently observed orientation dependent fracture toughness. A question that arises thereby is how the fracture properties for certain testing directions could be actively tuned by tailoring the grain aspect ratio. In this contribution this issue has been investigated by changing the aspect ratio of ultrafine-grained tantalum processed by high pressure torsion through post-rolling operations which induced a substantial increase of the grain length while keeping the strength on a comparable level. Samples in interesting testing directions were manufactured and tested. The increase of the aspect ratio results in the technically significant testing directions to an enhancement of the fracture toughness. Delamination toughening, which is promoted by the change of the aspect-ratio, has been indentified to be the main cause for the toughness enhancement and represents therefore a feasible pathway for optimizing the damage tolerance of SPD-processed materials.

KW - Fracture toughness

KW - Grain aspect ratio

KW - High pressure torsion

KW - Tantalum

KW - Ultrafine-grained

UR - http://www.scopus.com/inward/record.url?scp=85126601443&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2022.110545

DO - 10.1016/j.matdes.2022.110545

M3 - Article

AN - SCOPUS:85126601443

VL - 216.2022

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

IS - April

M1 - 110545

ER -