Stronger, tougher steels
Science: Steel is the workhorse of our infrastructure. Stronger, tougher steels are always needed to reduce weight and improve safety in transportation, enhance architectural flexibility in construction, and improve performance in heavy machinery. For structural steels to be both strong and tough (resistant to fracture), they must not be used at temperatures below the ductile-brittle transition temperature, TB, at which the steel loses its toughness and fractures in a brittle mode. This transition results from a competition between plastic deformation and brittle fracture at the tips of cracks or flaws in the steel. It can be controlled by techniques such as grain refinement that inhibit brittle fracture, or by techniques such as controlled delamination that facilitate plastic deformation. In last week's Science magazine, Yuuji Kimura, Tadanobu Inoue, Fuxing Yin, and Kaneaki Tsuzaki show how these approaches can be combined to achieve low TB and high toughness in an ultrahigh-strength low-alloy steel.
Related Links
Inverse Temperature Dependence of Toughness in an Ultrafine Grain-Structure Steel Science 320 1057 - 1060
Comments
The automotive industry should enjoy the development of the "low TB and high toughness in an ultrahigh-strength low-alloy steel". Portions of the cars’ and trucks’ transmissions and drive trains as well as engine components may well benefit from such steel.
The aerospace industry should enjoy this development also in so far as lighter structural frames for high G force capable manned space vehicles including perhaps single stage to orbit vehicles with a rapid turn around time are concerned.
The armed forces of various nations might use the steel or similar products to it for improved armoring of combat vehicles such as main battle tanks, APCs, armored gunships and the like.
Such steels can find use in the construction of steel reinforced buildings that must meet special terrorists’ bomb resistant designs. Perhaps the World Trade Center towers in NYC would have faired better, or at least have lasted long enough for most of the persons who were otherwise killed in the collapse of the buildings to escape to safety.
For long duration manned planetary missions, such as to Mars and beyond, perhaps this steel could be useful as protective shielding from micro meteors and other dust-like or small-grained natural debris in interplanetary space.
One can go on and on about the potential uses of such steels, but the main point, although obvious, is that major improvements in ubiquitous constructions materials such as that for the above mentioned steel have a profound effect on our infrastructure.
Posted by: James M. Essig | May 29, 2008 8:47 PM