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A super-hard metal has been made in the laboratory by melting together titanium and gold.
The alloy is the hardest known metallic substance compatible with living tissues, say US physicists.
The material is four times harder than pure titanium and has applications in making longer-lasting medical implants, they say.
Conventional knee and hip implants have to be replaced after about 10 years due to wear and tear.
Details of the new metal - an alloy of gold and titanium - are revealed in the journal, Science Advances.
Prof Emilia Morosan, of Rice University, Houston, said her team had made the discovery while working on unconventional magnets made from titanium and gold.
The new materials needed to be made into powders to check their purity, but beta-Ti3Au, as it is known, was too tough to be ground in a diamond-coated mortar and pestle.
The material "showed the highest hardness of all Ti-Au [titanium-gold] alloys and compounds, but also compared to many other engineering alloys", said Prof Morosan.
She said the hardness of the substance, together with its higher biocompatibility, made it a "next generation compound for substantively extending the lifetime of dental implants and replacement joints".
Source: http://www.bbc.com/news/science-environment-36855705
(Score: 2) by ikanreed on Monday July 25 2016, @05:43PM
One of the problems with ultra-hard materials is they have a narrow plastic band, and tend to fracture rather than bend.
It's why cars are safer now that they aren't made of ultra-hard steel anymore. They crumple efficiently and absorb the kinetic energy of the collision.
It's probably good for, as the article describes, bone replacement, since you don't want those to bend, but it's likely to be useless for industrial use because it'll develop micro-fractures under any sort of real stress.
(Score: 4, Informative) by SparkyGSX on Monday July 25 2016, @06:32PM
Indeed, the BBC article says it's four times harder and tougher than titanium; however, hardness and toughness are VERY different things. Actually, there are more or less opposites. Hardness refers to the resistance to plastic deformation, whereas toughness refers to the ability to absorb impacts, including plastic deformation without fracturing. Hard materials tend to be brittle, which means they will easily shatter instead of bending.
Glass is very hard, but it's not very tough. Aluminium, on the other hand, is reasonably tough, but not very hard at all.
If you do what you did, you'll get what you got
(Score: 0) by Anonymous Coward on Tuesday July 26 2016, @02:26AM
I thought the development in artificial joints was going toward ceramics? Lower heat conductivity reducing discomfort when changing outside temps and generally closer in properties to bone? Ceramics are being made in clever ways to increase fracture toughness.
(Score: 0) by Anonymous Coward on Tuesday July 26 2016, @03:35AM
...thus not getting you strip-searched by TSA because you didn't set off their little thingie.
Sounds good to me.
-- OriginalOwner_ [soylentnews.org]
(Score: 1) by anubi on Tuesday July 26 2016, @04:19AM
Another thing is lubrication... so the joint does not erode off toxic scrapings.
The joint is plenty sturdy, but like an engine with insufficient lubrication, scraping happens, and the moving surfaces wear out of tolerance pretty fast.
Now, the dental work looks like a good use for this. Natural tooth enamel is the hardest substance in the human body. A little will go a long way, and on top of that, the remains of worn previous installations can be melted down and re-cast.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by bradley13 on Tuesday July 26 2016, @06:39AM
Joints don't have to be replaced after 10 years - more like 25. I have a very active friend who got an artificial hip joint in his mid-40s. He is still playing football (soccer, for you Americans) 20 years later, and expects to need a replacement in 5-10 years.
As I understand it, the hardness of the material is not relevant beyond a certain point - lack of reactivity is more important. The problem with the joints is friction and wear, and these have surprisingly little to do with hardness. Nowadays, most joints use a plastic cup that has very low friction with the metal or ceramic ball; metal-on-metal joints produce metallic particles that cause inflammation in some patients.
For something really weird: look at the cost of hip replacement listed in Wikipedia: $40,000 in the USA, compared to around $10,000 anywhere else [wikipedia.org]. WTF?
Everyone is somebody else's weirdo.
(Score: 1) by anubi on Tuesday July 26 2016, @07:20AM
In America... insurance. Vendors ask for the moon... and get it.
Not only that, factor in the cost of that blonde bombshell that interrupts TV every five minutes informing everyone if they have ever had someone try to help them, and it went wrong, even years later, lawyers are standing by... who is paying for all this? US.
While the lawyers and ad-men live in mansions and have private jets and yachts on call, we have to scrape up whatever insurance premium demanded.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 3, Informative) by Immerman on Tuesday July 26 2016, @04:35PM
I'm not so sure about dental work either - with dental work you have two factors to consider - wear of the replacement material, and wear of the opposing tooth enamel because of the replacement material.
As it happens, one of the reasons gold crowns are popular among dentists is that they have almost exactly the same wear properties as tooth enamel - ceramic crowns are considerably harder and more wear resistant, which is great for them, but causes much accelerated wear of the enamel of the opposing teeth.