Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Titanium + gold = new gold standard for artificial joints

21.07.2016

Rice lab discovers titanium-gold alloy that is 4 times harder than most steels

Titanium is the leading material for artificial knee and hip joints because it's strong, wear-resistant and nontoxic, but an unexpected discovery by Rice University physicists shows that the gold standard for artificial joints can be improved with the addition of some actual gold.


This is the crystal structure of beta titanium-3 gold.

Credit: E. Morosan/Rice University

"It is about 3-4 times harder than most steels," said Emilia Morosan, the lead scientist on a new study in Science Advances that describes the properties of a 3-to-1 mixture of titanium and gold with a specific atomic structure that imparts hardness. "It's four times harder than pure titanium, which is what's currently being used in most dental implants and replacement joints."

Morosan, a physicist who specializes in the design and synthesis of compounds with exotic electronic and magnetic properties, said the new study is "a first for me in a number of ways. This compound is not difficult to make, and it's not a new material."

In fact, the atomic structure of the material -- its atoms are tightly packed in a "cubic" crystalline structure that's often associated with hardness -- was previously known. It's not even clear that Morosan and former graduate student Eteri Svanidze, the study's lead co-author, were the first to make a pure sample of the ultrahard "beta" form of the compound. But due to a couple of lucky breaks, they and their co-authors are the first to document the material's remarkable properties.

"This began from my core research," said Morosan, professor of physics and astronomy, of chemistry and of materials science and nanoengineering at Rice. "We published a study not long ago on titanium-gold, a 1-to-1 ratio compound that was a magnetic material made from nonmagnetic elements. One of the things that we do when we make a new compound is try to grind it into powder for X-ray purposes. This helps with identifying the composition, the purity, the crystal structure and other structural properties.

"When we tried to grind up titanium-gold, we couldn't," she recalled. "I even bought a diamond (coated) mortar and pestle, and we still couldn't grind it up."

Morosan and Svanidze decided to do follow-up tests to determine exactly how hard the compound was, and while they were at it, they also decided to measure the hardness of the other compositions of titanium and gold that they had used as comparisons in the original study.

One of the extra compounds was a mixture of three parts titanium and one part gold that had been prepared at high temperature.

What the team didn't know at the time was that making titanium-3-gold at relatively high temperature produces an almost pure crystalline form of the beta version of the alloy -- the crystal structure that's four times harder than titanium. At lower temperatures, the atoms tend to arrange in another cubic structure -- the alpha form of titanium-3-gold. The alpha structure is about as hard as regular titanium. It appears that labs that had previously measured the hardness of titanium-3-gold had measured samples that largely consisted of the alpha arrangement of atoms.

The team measured the hardness of the beta form of the crystal in conjunction with colleagues at Texas A&M University's Turbomachinery Laboratory and at the National High Magnetic Field Laboratory at Florida State University, Morosan and Svanidze also performed other comparisons with titanium. For biomedical implants, for example, two key measures are biocompatibility and wear resistance. Because titanium and gold by themselves are among the most biocompatible metals and are often used in medical implants, the team believed titanium-3-gold would be comparable. In fact, tests by colleagues at the University of Texas MD Anderson Cancer Center in Houston determined that the new alloy was even more biocompatible than pure titanium. The story proved much the same for wear resistance: Titanium-3-gold also outperformed pure titanium.

Morosan said she has no plans to become a materials scientist or dramatically alter her lab's focus, but she said her group is planning to conduct follow-up tests to further investigate the crystal structure of beta titanium-3-gold and to see if chemical dopants might improve its hardness even further.

###

Additional co-authors include Pulickel Ajayan, Sruthi Radhakrishnan and Chandra Sekhar Tiwary, all of Rice; Tiglet Besara, Yan Xin, Ke Han and Theo Siegrist, all of Florida State; Fevzi Ozaydin and Hong Liang, both of Texas A&M; and Sendurai Mani of MD Anderson. The research was supported by the National Science Foundation, the Department of Energy, Texas A&M's Turbomachinery Laboratory and the Florida State University Research Foundation.

This release can be found online at news.rice.edu.

Follow Rice News and Media Relations on Twitter @RiceUNews.

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,910 undergraduates and 2,809 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview.

Media Contact

David Ruth
david@rice.edu
713-348-6327

 @RiceUNews

http://news.rice.edu 

David Ruth | EurekAlert!

More articles from Health and Medicine:

nachricht Investigators may unlock mystery of how staph cells dodge the body's immune system
22.09.2017 | Cedars-Sinai Medical Center

nachricht Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>