And also because maraging steels are one of my favorite topics, here goes.
"Mar" does indeed come from "martensite," that has all the properties Jackie mentioned. "Aging" is not as self explanatory as you might think. I'll explain in a moment.
"Maraging" means "martensitic, aging" steel. It is both. Most steels that one thinks of as high-strength are martensitic (having martensite). There are other materials (7075 and 6061 Aluminums) that harden as they age. This happens when precipitates (elements that come out of solution) grow and create favorable stresses inside the material. This happens over many years (usually) unless artificially accelerated. Maraging steels have the benefits of the martensite, making them hard and strong, and the benefits of the aging of precipitates as well. The process to artificially age the steel also "tempers" or "draws" the martensite, so it no longer acts like glass (reference metallurgical histories on "liberty ships" for more info). It is therefore ductile and tough. Now, some maraging steels (contrary to previous reports) are also corrosion resistant (high nickel, cobalt contents). So it has all four attributes, making it the supermaterial - right? Wrong. No such thing. Maraging steels are particularly vulnerable to heat, losing all their good properties when used for any length of time over 250 deg C.
Maraging steels, esp. corrosion resistant ones, make excellent blades and are used in medical applications. If you had the know-how, you could make a sword that would defeat any weapon made to date (100,000 folded Japanese swords, Damascus steel, and Toledo steel notwithstanding). As a room-temperature metal, it is hard to beat - but it is very expensive and takes a great deal of know-how and technology to manufacture.
Hope that helps.
Cheers,
Bryan
