Hard metals are also known as cemented carbides and are most commonly tungsten carbide particles bound together with cobalt, though they can include other carbides and/or use a nickel binder. Micrograin refers to the size of the carbide particles (about 1 micrometer).

You could also use micrograin hardmetal or micrograin cemented carbide, though a Google search gives more references to micrograin hard metal - which surprises me. I always used the other two in preference!