[HN Gopher] The Toughest Material on Earth
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       The Toughest Material on Earth
        
       Author : bilsbie
       Score  : 27 points
       Date   : 2022-12-11 18:36 UTC (4 hours ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | moloch-hai wrote:
       | I thought the toughest material was produced by cephalopods, by a
       | process we cannot hope to reproduce. Are different definitions of
       | toughness in play?
        
         | ghaff wrote:
         | I think you'll probably find it's one of the toughest organic
         | materials. But there's certainly an interest in taking
         | inspiration from such materials for other purposes.
        
       | bryan0 wrote:
       | I think this article is missing a basic definition of
       | "toughness".
       | 
       | > In materials science and metallurgy, toughness is the ability
       | of a material to absorb energy and plastically deform without
       | fracturing.
       | 
       | https://en.m.wikipedia.org/wiki/Toughness
        
         | eesmith wrote:
         | And measured in units I've not heard of before. The toughness
         | was "as high as 500 megapascals square root meters".
        
           | ghaff wrote:
           | I had to double-check given how old my knowledge in this area
           | is but MPa m^1/2 does indeed seem to be the unit used to
           | measure toughness using diamond indenters etc. More
           | precisely, it apparently describes the Fracture toughness,
           | which is an indication of the tendency of the material to
           | allow for a free propagation of a crack while under stress.
           | The higher the value, the more energy the material absorbs
           | and less freely does the crack propagate.
           | 
           | (Toughness modulus is in Pascals.)
        
       | ahazred8ta wrote:
       | A chromium, cobalt, nickel alloy (CrCoNi / CrMnFeCoNi) which is
       | fracture resistant even at cryogenic temperatures.
        
       | ghaff wrote:
       | My master's thesis ended up being basically studying a lot of the
       | basic material characteristics of about a 50:50 alloy of nickel
       | and aluminum. (This article is about an alloy with a significant
       | mix of three elements as part of a class of materials that
       | combine even more in significant quantities.)
       | 
       | My thesis advisor was trying to find out ways to present this
       | class of alloys from becoming brittle when heated. The research
       | never really produced good results though and he ended being
       | mostly focused on studying (water) ice.
        
       | [deleted]
        
       | tomcam wrote:
       | This is all bull. Anyone who's had a toddler swing their dense
       | little head at you and was rewarded with a fat lip knows exactly
       | what the hardest material on earth is. My startup, BabySkull.io
       | (YC S23), is exploring this material for defense-related
       | equipment.
        
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       (page generated 2022-12-11 23:02 UTC)