A new iron based superelastic alloy capable of withstanding extreme temperatures

Date:
August 20, 2020
Source:
Tohoku University
Summary:
Researchers have discovered a novel iron-based superelastic alloy
(SEA) capable of withstanding extreme temperatures--both high
and low.



FULL STORY ========================================================================== Researchers from Tohoku University's Graduate School of Engineering
have discovered a novel iron-based superelastic alloy (SEA) capable of withstanding extreme temperatures -both high and low.


==========================================================================
SEAs are found in a wide variety of commercial applications because
of their superelasticity, allowing them to regain their original
shape. Superelasticity occurs when the metal undergoes deformation at
the point known as critical stress.

Generally, SEAs have a positive temperature dependence; the critical
stress increases as the temperature rises. Conventional metal-based SEAs
such as Ti- Ni, cannot be used at temperatures lower than -20C or higher
than 80C and are costly to make. This limits their application to the
form of thin wires or tubes.

Associate Professor at Tohoku University, Toshihiro Omori and his team developed an iron-based SEA system, known as Fe-Mn-Al-Cr-Ni. This cost- effective SEA can also operate at a much wider temperature range.

A significant advantage of the new SEA is its controllable temperature dependence. Increasing the amount of Chromium allowed the researchers to
change the temperature dependence from a positive to a negative. Balancing
the Chromium content resulted in zero temperature dependence with the
critical stress remaining almost constant at various temperatures.

The discovery possesses wide-spread application for outer-space
exploration given the large temperature fluctuations that occur," says Professor Omori." Omori points to the fact that NASA is developing a superelastic tire that can withstand excessive deformation for Moon and
Mars missions. The temperature differences between night and day on the
Moon and Mars are -170C to 120C and - 150C to 20C respectively.

"Yet, the new, SEA's usage does not stop there." Professor Omori adds,
"It can potentially be used in tension braces in buildings or column
elements in bridges -- providing greater resistance to earthquakes."
The discovery possesses wide-spread application for outer-space
exploration given the large temperature fluctuations that occur," says Professor Omori." Omori points to the fact that NASA is developing a superelastic tire that can withstand excessive deformation for Moon and
Mars missions. The temperature differences between night and day on the
Moon and Mars are -170C to 120C and - 150C to 20C respectively.

"Yet, the new, SEA's usage does not stop there." Professor Omori adds,
"It can potentially be used in tension braces in buildings or column
elements in bridges -- providing greater resistance to earthquakes."

========================================================================== Story Source: Materials provided by Tohoku_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Ji Xia, Yuki Noguchi, Xiao Xu, Takumi Odaira, Yuta Kimura, Makoto
Nagasako, Toshihiro Omori, Ryosuke Kainuma. Iron-based superelastic
alloys with near-constant critical stress temperature dependence.

Science, 2020; 369 (6505): 855 DOI: 10.1126/science.abc1590 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200820102436.htm

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