Case 13519

Thermo-mechanical process for enhanced quality of grain boundary networks in high-purity metals

Keywords:

Crystallographic grain boundary, electroplating, uniformity of dissolution, grain boundary engineering, thermo-mechanical process, isothermal deformation

Applications:

High-purity metals including various kinds of face centered cubic (FCC) metals such as pure copper, other copper alloys, brass, pure nickel, nickel alloys and various kinds of austenitic stainless steels for

  • Uniformity of dissolution for anode materials (Cu, Ni and their alloys etc)
  • Higher mechanical strength and higher resistivity to softening during usage time as electric connecting plate materials (Cu and Cu alloys)
  • Creep resistance at elevated temperatures
  • Weldability and hot cracking resistance
  • Stress-corrosion cracking resistance

Problem:

    The most effective Grain Boundary Engineering (GBE) technologies reported to date involve many cycles of cold work/hot annealing, which would be especially inefficient in practice at large scales.

Technology:

This invention is a new method of changing the internal structure of metals through a process of deformation and annealing. It pertains to changing the crystallographic types of grain boundaries to increase the fraction of “special” grain boundaries and to tailor desirable physical and chemical properties in metals. Instead of running cycles of "deformation at ambient temperature" and "annealing at apparently higher temperature than ambient temperature", the new isothermal thermo-mechanical process can help avoid time and energy-consuming heating or cooling steps.

Advantages:
  • More effective that previously known grain boundary engineering (GBE) processes
  • Avoids time and energy-consuming heating or cooling steps
  • Applicable to various kinds of FCC metals, not just pure copper

Inventors:
  • Professor Christopher Schuh (Department of Materials Science and Engineering, MIT)
  • Koichi Kita (Department of Materials Science and Engineering, MIT)

Intellectual Property:

U.S. Patent Application Number 12/544568, filed on August 20, 2009

Publications:

N/A

Related Cases:

14063: Processing method of Cu alloy to get high coincident site lattice ratio grain boundaries

Last revised: April 29, 2013

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