Effect of bimodal harmonic structure design on the deformation behaviour and mechanical properties of Co-Cr-Mo alloy

Sanjay Kumar Vajpai; Choncharoen Sawangrat; Osamu Yamaguchi; Octav Paul Ciuca; Kei Ameyama

doi:10.1016/j.msec.2015.09.055

Effect of bimodal harmonic structure design on the deformation behaviour and mechanical properties of Co-Cr-Mo alloy

Mater Sci Eng C Mater Biol Appl. 2016 Jan 1:58:1008-15. doi: 10.1016/j.msec.2015.09.055. Epub 2015 Sep 16.

Authors

Sanjay Kumar Vajpai¹, Choncharoen Sawangrat², Osamu Yamaguchi³, Octav Paul Ciuca⁴, Kei Ameyama⁵

Affiliations

¹ Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan. Electronic address: vajpaisk@gmail.com.
² Department of Industrial Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand. Electronic address: choncharoen@step.cmu.ac.th.
³ Department of Mechanical Engineering, College of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan. Electronic address: rm0011xh@ed.ritsumei.ac.jp.
⁴ A14, Materials Science Centre, University of Manchester, Manchester, M1 7HS, England. Electronic address: octav.ciuca@manchester.ac.uk.
⁵ Department of Mechanical Engineering, College of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan. Electronic address: ameyama@se.ritsumei.ac.jp.

PMID: 26478398
DOI: 10.1016/j.msec.2015.09.055

Abstract

In the present work, Co-Cr-Mo alloy compacts with a unique bimodal microstructural design, harmonic structure design, were successfully prepared via a powder metallurgy route consisting of controlled mechanical milling of pre-alloyed powders followed by spark plasma sintering. The harmonic structured Co-Cr-Mo alloy with bimodal grain size distribution exhibited relatively higher strength together with higher ductility as compared to the coarse-grained specimens. The harmonic Co-Cr-Mo alloy exhibited a very complex deformation behavior wherein it was found that the higher strength and the high retained ductility are derived from fine-grained shell and coarse-grained core regions, respectively. Finally, it was observed that the peculiar spatial/topological arrangement of stronger fine-grained and ductile coarse-grained regions in the harmonic structure promotes uniformity of strain distribution, leading to improved mechanical properties by suppressing the localized plastic deformation during straining.

Keywords: Bimodal grain structure; Co-Cr-Mo alloy; Deformation mechanism; Harmonic structure; Powder metallurgy; Severe plastic deformation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Alloys / chemistry*
Chromium / chemistry
Cobalt / chemistry
Hardness Tests
Molybdenum / chemistry
Tensile Strength

Substances

Alloys
Chromium
Cobalt
Molybdenum