When he left the University of Michigan, Paul Krajewski was an expert in “creep” behavior related to all things aluminum. In the jargon of metallurgy, creep is heat- and stress-related deformation, and it’s part of the reason aluminum is tricky to use for making cars. Aluminum is about 67 percent lighter than steel, but it is far more susceptible to cracking when deformed. Today Krajewski is a leading materials scientist at General Motors, devising ways to engineer aluminum so it can be used in mass production of lighter and more fuel-efficient family sedans and SUVs instead of just pricey handmade exotic cars. Krajewski invented a flash-heating technique that allows aluminum to bend on the assembly line without cracking. To ease one manufacturing process, he even developed a lubricant using milk of magnesia. Krajewski has won seven patents related to his techniques, which will help General Motors build cars with “creases and curves, anything that would excite the eyes of the customer,” he says. And those lightweight parts should also excite customers when they get to the gas pump.