50 years ago, steel got stronger and stretchier

Excerpt from the August 19, 1967, issue of Science News

BUILDING UP TO IT  Scientists are still trying to make steel, an architectural mainstay, stronger but not too brittle.


Ductile, strong steel

Fundamental scientific knowledge of the behavior of metallic crystals has led to the design of a new series of alloy steels, stronger and tougher than those now available. The new alloys can be stretched from two to five times more than previous ones, yet also have high strength…. The alloys, called TRIP steels, are produced by [the process] Transformation Induced Plasticity. — Science News, August 19, 1967


TRIP steels are still used in cars. But the quest for a strong, lightweight steel continues, spurred by better knowledge of how a material’s nanostructure affects its overall properties. One surprising approach: embedding tiny, brittle iron-aluminum grains within steel. A bit of nickel helps position the grains properly and prevents small cracks from spreading, researchers reported in 2015 in Nature. Another method makes steel with variable nanoscale layers, similar to bone (SN: 4/15/17, p. 5). The inconsistent microstructure disrupts emerging cracks, preventing them from traveling in a straight line.

SUPER STEEL Embedding small nickel-aluminum grains (bubble, top left) into the microstructure of steel can keep cracks from spreading in a straight line, as seen in this microscope image. S.-H. Kim et al/Nature 2015

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