tag:blogger.com,1999:blog-1592992209402300549.post6261751337432315197..comments2024-03-28T08:06:43.198-04:00Comments on The Silicon Graybeard: Techy Tuesday - Transparent Armor SiGraybeardhttp://www.blogger.com/profile/00280583031339062059noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-1592992209402300549.post-25989210763678463452014-12-04T22:26:58.309-05:002014-12-04T22:26:58.309-05:00From what little I remember about metals, grain st...From what little I remember about metals, grain structure was significant, but not analogous to crystalline lattice structure, amorphous crystal structure, etc. Too deep for me, but it is interesting how different materials respond in the various ways they are strong and weak, vulnerable to outside forces - physical, chemical, etc.. Like the compressive strength of an egg shell along one axis, but not another.<br /><br />These new materials are fascinating. Thanks for the post and the response.Reg Thttps://www.blogger.com/profile/14099612693763932005noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-4756495080443654032014-12-03T18:33:47.728-05:002014-12-03T18:33:47.728-05:00It does happen in metals, but I'd be cautious ...It does happen in metals, but I'd be cautious about comparing metals and nonmetals, especially crystals. Diamonds are insanely hard, due to the covalent carbon-carbon bonds. But they cleave perfectly along bond planes, so they crush easily. <br /><br />Undergraduate mechanical engineers are required to take a class often called strength of materials. It's a complex subject and a tough class. Take glass, which is great in compression - I'm sure you've been in building with architectural glass blocks in the walls. Glass is brittle and doesn't bend, it just snaps. Strong in one direction, but not in another. <br /><br />I woud guess they chose spinel for reasons related to how tough it is and how hard it might be to break, not its scratch resistance. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-11008482547322371912014-12-02T23:33:46.619-05:002014-12-02T23:33:46.619-05:00And don't very hard materials often tend to be...And don't very hard materials often tend to be brittle, as happens with some metals? Or am I misconstruing that?Reg Thttps://www.blogger.com/profile/14099612693763932005noreply@blogger.com