Strengthening of Alloys with Elastic Anisotropy by Severe Plastic Deformation

Abstract:

Effects of the elastic anisotropy on deformation behavior are examined in a Ti-23%Nb-0.7%Ta-2%Zr-1.2%O (in at %) alloy, Gum Metal, and in an Fe-19%Ni-34%Co-8%Ti alloy with body centered cubic (bcc) crystal structure, and microstructural development in the iron based alloy during severe plastic deformation (SPD) process is discussed. Strong elastic anisotropy with reduced shear modulus, C₁₁- C₁₂, results in low ideal shear strength, which implies dislocation mediated plasticity easily occurs at lower stress. On the other hand, high pressure torsion (HPT), a typical SPD method, realizes very high shear stress during processing, which seems to reach the ideal shear strength in these alloys. Significant refinement of the grain size to 20 - 50 nm in the Fe-Ni-Co-Ti alloy is discussed in relation to the unique deformation mechanism which might be activated at ideal shear strength.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 1799-1804
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.1799
• Online since: January 2012
• Authors: Shigeru Kuramoto, Tadahiko Furuta, Naoyuki Nagasako, Z. Horita
• Keywords: Dislocation, Elastic Deformation, Grain Refinement, High Pressure Torsion (HPT), Iron Alloys, Plastic Deformation, Titanium Alloy, Work-Hardening

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