Case 14063

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

Keywords:

CSL grain boundary, GBE, alloy

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

These properties and others can be enhanced by very large factors (up to 10x) by grain boundary engineering (GBE).

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. The recent development of this technology proposes a new process of GBE. It is applied to Cu alloys that exhibit second-phase precipitation, and provides an appropriate GBE process for those alloys.

Advantages:
  • A drop-in processing method to enhance the properties of common alloys by very large factors (10x)
  • More effective than previously known grain boundary engineering (GBE) processes
  • Avoids time and energy-consuming heating or cooling steps
  • Applicable to various kinds of FCC metals, specifically applicable to those that precipitate second phases

Inventors:
  • Professor Christopher A. Schuh(MIT, Department of Material Science and Engineering)
  • Kenichi Yaguchi (MIT, Department of Material Science and Engineering)

Intellectual Property:

US Patent Application Number 13/019124, filed on February 1, 2011

PCT Patent Application Number PCT/US2012/023458, filed on February 1, 2012

Publications:

N/A

Related Cases:

13519: Thermo-mechanical process for enhanced quality of grain boundary networks in high-purity metals

Last revised: April 29, 2013

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