TY - JOUR
T1 - High-pressure torsion of palladium
T2 - Hydrogen-induced softening and plasticity in ultrafine grains and hydrogen-induced hardening and embrittlement in coarse grains
AU - Hongo, Toshifumi
AU - Edalati, Kaveh
AU - Iwaoka, Hideaki
AU - Arita, Makoto
AU - Matsuda, Junko
AU - Akiba, Etsuo
AU - Horita, Zenji
N1 - Funding Information:
One of the authors (KE) thanks the Japan Society for Promotion of Science ( JSPS ) for a Grant-in-Aid for Research Activity from the MEXT, Japan (No. 25889043 ). This work was supported in part by WPI-I2CNER , and in part by a Grant-in-Aid for Scientific Research from the MEXT , Japan, in Innovative Areas “Bulk Nanostructured Metals” (No. 22102004 ).
Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Pure Pd (99.9%) was processed by high-pressure torsion (HPT) to form an ultrafine-grained (UFG) structure with an average grain size of ~220. nm, high hardness of 175. Hv, high tensile strength of 650. MPa and appreciable plasticity of 20%. Tensile tests showed that, unlike coarse-grained sample in which a hydrogen-induced embrittlement and hardening occurred, a hydrogen-induced softening and plasticity occurred in the HPT-processed UFG sample. A hydride phase formed after exposing the samples to hydrogen, while the formation of hydride was facilitated by the HPT processing. The hydride phase was decomposed by holding the samples in the air for prolonged time, but the hydride phase was more stable after HPT processing.
AB - Pure Pd (99.9%) was processed by high-pressure torsion (HPT) to form an ultrafine-grained (UFG) structure with an average grain size of ~220. nm, high hardness of 175. Hv, high tensile strength of 650. MPa and appreciable plasticity of 20%. Tensile tests showed that, unlike coarse-grained sample in which a hydrogen-induced embrittlement and hardening occurred, a hydrogen-induced softening and plasticity occurred in the HPT-processed UFG sample. A hydride phase formed after exposing the samples to hydrogen, while the formation of hydride was facilitated by the HPT processing. The hydride phase was decomposed by holding the samples in the air for prolonged time, but the hydride phase was more stable after HPT processing.
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U2 - 10.1016/j.msea.2014.08.074
DO - 10.1016/j.msea.2014.08.074
M3 - Article
AN - SCOPUS:84907551989
VL - 618
SP - 1
EP - 8
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -