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UCLA researchers develop exceptionally strong and lightweight new metal nanocomposite

A team led by researchers from the UCLA Henry Samueli School of Engineering and Applied Science has created a super-strong yet light structural metal nanocomposite with extremely high specific strength and modulus, or stiffness-to-weight ratio. The new metal is composed of magnesium infused with a dense and even dispersal of ceramic silicon carbide nanoparticles. It could be used to make lighter airplanes, spacecraft, and cars, helping to improve fuel efficiency, as well as in mobile electronics and biomedical devices.

To create the super-strong but lightweight metal, the team developed a new way to disperse and stabilize nanoparticles in molten metals. They also developed a scalable manufacturing method that could pave the way for more high-performance lightweight metals. A paper on their work is published today in Nature.

Magnesium+comparison_0c05ef44-03a5-44be-ad60-97d3ff88351e-prv
At left, a deformed sample of pure metal; at right, the strong new metal made of magnesium with silicon carbide nanoparticles. Each central micropillar is about 4 micrometers across. Source: UCLA. Click to enlarge.

It’s been proposed that nanoparticles could really enhance the strength of metals without damaging their plasticity, especially light metals like magnesium, but no groups have been able to disperse ceramic nanoparticles in molten metals until now. With an infusion of physics and materials processing, our method paves a new way to enhance the performance of many different kinds of metals by evenly infusing dense nanoparticles to enhance the performance of metals to meet energy and sustainability challenges in today’s society.

—Xiaochun Li, the principal investigator on the research and Raytheon Chair in Manufacturing Engineering at UCLA

Structural metals are load-bearing metals; they are used in buildings and vehicles. Magnesium, at just two-thirds the density of aluminum, is the lightest structural metal. Silicon carbide is an ultra-hard ceramic commonly used in industrial cutting blades. The researchers’ technique of infusing a large number of silicon carbide particles smaller than 100 nanometers into magnesium added significant strength, stiffness, plasticity and durability under high temperatures.

The researchers’ new silicon carbide-infused magnesium demonstrated record levels of specific strength—how much weight a material can withstand before breaking—and specific modulus—the material’s stiffness-to-weight ratio. It also showed superior stability at high temperatures.

Ceramic particles have long been considered as a potential way to make metals stronger. However, with microscale ceramic particles, the infusion process results in a loss of plasticity.

Nanoscale particles, by contrast, can enhance strength while maintaining or even improving metals’ plasticity. But nanoscale ceramic particles tend to clump together rather than dispersing evenly, due to the tendency of small particles to attract one other.

To counteract this issue, the researchers dispersed the particles into a molten magnesium zinc alloy. The newly discovered nanoparticle dispersion relies on the kinetic energy in the particles’ movement. This stabilizes the particles’ dispersion and prevents clumping.

To further enhance the new metal’s strength, the researchers used a technique called high-pressure torsion to compress it.

The results we obtained so far are just scratching the surface of the hidden treasure for a new class of metals with revolutionary properties and functionalities.

—Xiaochun Li

The new metal is about 14% silicon carbide nanoparticles and 86% magnesium. The researchers noted that magnesium is an abundant resource and that scaling up its use would not cause environmental damage.

The paper’s lead author is Lian-Yi Chen, who conducted the research as a postdoctoral scholar in Li’s Scifacturing Laboratory at UCLA. Chen is now an assistant professor of mechanical and aerospace engineering at Missouri University of Science and Technology.

The paper’s other authors from UCLA include Jia-Quan Xu, a graduate student in materials science and engineering; Marta Pozuelo, an assistant development engineer; and Jenn-Ming Yang, professor of materials science and engineering.

The other authors on the paper are Hongseok Choi, of Clemson University; Xiaolong Ma, of North Carolina State University; Sanjit Bhowmick of Hysitron, Inc. of Minneapolis; and Suveen Mathaudhu of UC Riverside.

The research was funded in part by the National Institute of Standards and Technology.

Resources

  • Lian-Yi Chen, Jia-Quan Xu, Hongseok Choi, Marta Pozuelo, Xiaolong Ma, Sanjit Bhowmick, Jenn-Ming Yang, Suveen Mathaudhu & Xiao-Chun Li (2015) “Processing and properties of magnesium containing a dense uniform dispersion of nanoparticles” Nature 528, 539–543 doi: 10.1038/nature16445

Comments

HarveyD

Seems to be a win-win potential future light weight multiple uses material? Various mixes could most probably bring various advantages for aerospace vehicles, airplanes and lighter rugged ground vehicles.

mahonj

A good week for the space industry: Space-X lands a booster back onto it's tail and now this new material.

OK, so it will take a few years to get into production, but the potential seems vast (space, then aerospace, then ground transportation).

(Pity about the A320 Neo engine problems and the MRJ 12 month delay).

Treehugger

Looks like Nice technically speaking, but could such an alloy be recycled? If not then they should develop it, we need recyclable material, composites are not great in that regard

Engineer-Poet

If you can't re-melt and re-form this nanocomposite, you can always separate it by electrowinning to metal and nanoparticle streams.

Alex_C

Very promising CHINO-INDIAN invention.
Just look at the names of scientists.
It's almost a rule for scientific articles published on this site, last almost 10 years.
Where are the US born scientists?

Engineer-Poet

The US-born are channeled into fields like law and business by low salaries for scientists and university admissions departments which prefer the higher tuitions paid by foreign students.

mahonj

The genius of the USA is to attract the brightest and best from all the world into their universities. Whether they stay is another matter. While the initial IP will go to UCLA, if the guys go back to China, who knows what will happen ?

Engineer-Poet

Even one lost generation of American inventors and researchers is a terrible, terrible thing.

mahonj

I think we are getting a bit melodramatic here. The US is by far the most inventive country in the world, due to its combination of brains and capital and expertise.

The Japanese (who were doing well for a while) are aghast at the ipod (!) and iphone as they used to be kings of electronics, but they are playing catch up now.

If some of the brains are imported, what does it matter, they bring ideas and hard work with them.

JMartin

@mohonj: You are correct, but they are certain to go back to China with the current US immigration laws. Anyone can come and pay tuition for advanced degrees, but then when they want to stay and build the economy, we send them away. Genius, for sure.

Engineer-Poet

If they stay, they can make plenty of money doing industrial espionage.

mahonj

If they stay, they can make plenty of money just working for US companies.

Engineer-Poet

But Americans aren't going to decamp back to China when they get an attractive enough offer.

JMartin

It is an immigration issue, not an economic issue.

HarveyD

In the not too distant future, industrial espionage, patents, massive investments, complex mass production, higher education, etc may be carried out the other way around to satisfy the Asian market.

India has been training more top Engineers and Programmers than USA for a few years. China may soon do so too? With close to 3 billion people, and growing fast, those two nations may lead in many field within 30 to 40 years.

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