TY - JOUR

T1 - Micro-Mechanical Fracture Investigations on Grain Size Tailored Tungsten-Copper Nanocomposites

AU - Schmuck, Klemens Silvester

AU - Burtscher, Michael

AU - Alfreider, Markus

AU - Wurmshuber, Michael

AU - Kiener, Daniel

N1 - Publisher Copyright: © 2024, The Author(s).

PY - 2024/5

Y1 - 2024/5

N2 - Tungsten-copper composites are used in harsh environments because of their superior material properties. This work addresses a tungsten-copper composite made of 20 wt.% copper, which was subjected to grain refinement by high-pressure torsion, whereby the deformation temperature was varied between room temperature and 400 °C to tailor the grain size. Deformation was performed up to microstructural saturation and verified by hardness measurement and scanning electron microscopy. From the refined nanostructured material, micro-cantilever bending beams with cross-sections spanning from 5 × 5 to 35 × 35 µm 2 were cut to examine possible size effects and the grain size influence on the fracture behavior. Fracture experiments were performed in situ inside a scanning electron microscope by applying a quasi-static loading protocol with partial unloading steps. Inspection of the fracture surfaces showed that all cantilevers failed in an inter-crystalline fashion. Nevertheless, remaining coarser tungsten grains impacted the resultant fracture toughness and morphology. Cantilevers fabricated from the 400 °C specimen exhibited a fracture toughness of 220 ± 50 Jm2 . For the room temperature cantilevers, a fracture toughness of 410 ± 50 Jm2 was observed, which declined to 340 ± 30 Jm2 for cantilevers < 10 × 10 µm 2, confirming a size effect. The increased fracture toughness is attributed to the delamination-like structures formed in the room temperature sample.

AB - Tungsten-copper composites are used in harsh environments because of their superior material properties. This work addresses a tungsten-copper composite made of 20 wt.% copper, which was subjected to grain refinement by high-pressure torsion, whereby the deformation temperature was varied between room temperature and 400 °C to tailor the grain size. Deformation was performed up to microstructural saturation and verified by hardness measurement and scanning electron microscopy. From the refined nanostructured material, micro-cantilever bending beams with cross-sections spanning from 5 × 5 to 35 × 35 µm 2 were cut to examine possible size effects and the grain size influence on the fracture behavior. Fracture experiments were performed in situ inside a scanning electron microscope by applying a quasi-static loading protocol with partial unloading steps. Inspection of the fracture surfaces showed that all cantilevers failed in an inter-crystalline fashion. Nevertheless, remaining coarser tungsten grains impacted the resultant fracture toughness and morphology. Cantilevers fabricated from the 400 °C specimen exhibited a fracture toughness of 220 ± 50 Jm2 . For the room temperature cantilevers, a fracture toughness of 410 ± 50 Jm2 was observed, which declined to 340 ± 30 Jm2 for cantilevers < 10 × 10 µm 2, confirming a size effect. The increased fracture toughness is attributed to the delamination-like structures formed in the room temperature sample.

UR - https://pureadmin.unileoben.ac.at/portal/en/publications/micromechanical-fracture-investigations-on-grain-size-tailored-tungstencopper-nanocomposites(d3378b5e-2db6-4555-ae23-ec4ee700fd29).html

UR - http://www.scopus.com/inward/record.url?scp=85181890220&partnerID=8YFLogxK

U2 - 10.1007/s11837-023-06348-7

DO - 10.1007/s11837-023-06348-7

M3 - Article

VL - 76.2024

SP - 2302

EP - 2314

JO - JOM

JF - JOM

SN - 1047-4838

IS - May

ER -