ITHACA, New York, Jan. 9 -- Cornell University posted the following news:

* * *

Supersonic tests defy a 70-year-old rule of metal strength

*

When engineers want to make a metal stronger, one of the most reliable strategies is to use smaller grains - the microscopic crystal regions within the material. But when deformed at extreme speeds, this rule flips and metals with very small grains actually become softer, new Cornell research reveals.