I just spotted this article about a metal foam that stops armor-piercing bullets as well as radiation. It's a press article, not a scholarly paper, so it may be complete bunk. And rifle bullets are amazingly slow relative to just about any object wandering around in orbit. However, metal foam seems like something that could be "easily" manufactured in a Lunar environment.
Is making a habitat shell out of material like this going to be significantly helpful, or are meteorites just going to punch through it anyway?