{"id":14736,"date":"2018-03-21T06:17:38","date_gmt":"2018-03-21T06:17:38","guid":{"rendered":"https:\/\/www.revoscience.com\/en\/?p=14736"},"modified":"2020-05-27T06:05:06","modified_gmt":"2020-05-27T06:05:06","slug":"liquid-to-glass-transition-process-gains-clarity","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/liquid-to-glass-transition-process-gains-clarity\/","title":{"rendered":"Liquid-to-glass transition process gains clarity"},"content":{"rendered":"
\"\"
Paul Voyles<\/figcaption><\/figure>\n

For millennia, people have used molten sand and other ingredients to create glass and fashion beads, vessels, lenses and windows.<\/span><\/p>\n

These days, metallic glasses \u2014 made entirely of metal atoms \u2014 are being developed for biomedical applications such as extra-sharp surgical needles, stents, and artificial joints or implants because the alloys can be ultra-hard, extra strong, very smooth and resistant to corrosion.<\/span><\/p>\n

While a combination of trial and error and scientific research helped refine glassmaking processes over time, controlling the creation of metallic glasses at the atomic level remains an inexact endeavor informed largely by long experience and intuition.<\/span><\/p>\n

\u201cOur job,\u201d says\u00a0Paul Voyles<\/a>, \u201cis to build fundamental understanding by adding more data.\u201d<\/span><\/p>\n

The Beckwith-Bascom Professor in materials science and engineering at the University of Wisconsin\u2013Madison, Voyles and collaborators in Madison and at Yale University have made significant experimental strides in understanding how, when and where the constantly moving atoms in molten metal \u201clock\u201d into place as the material transitions from liquid to solid glass.<\/span><\/p>\n

They described what they observed about how those atoms rearrange at different temperatures over time today (March 19, 2018) in the journal\u00a0Nature Communications<\/a>. It\u2019s knowledge that can add much-needed experimental clarity to several competing theories about how that process, called the glass transition, occurs. It also could help reduce time and costs associated with developing new metallic glass materials, and provide manufacturers greater insight into process design.<\/span><\/p>\n

One processing challenge is that as metals transitions from molten liquid to solid, they tend to form orderly, regularly repeating atomic structures called crystals. In contrast, glass materials have a highly disordered atomic structure. And while making a high-performance metallic glass sounds as simple as preventing metal atoms from forming crystals as the material cools, in reality, it relies somewhat on the luck of the draw.<\/span><\/p>\n

\u201cThe process that makes a glass and the process that makes a crystal compete with each other, and the one that wins \u2014 the one that happens at a faster rate \u2014 determines the final product,\u201d says Voyles, whose work is supported by the National Science Foundation and U.S. Department of Energy.<\/span><\/p>\n

In a liquid, all of the atoms are moving past each other at all times. As a molten metal cools, and begins its transition to a solid, its atoms slow down and eventually stop moving.<\/span><\/p>\n

It\u2019s a complicated atomic-level dance that scientists are still unraveling. Drawing on their expertise in electron microscopy and data analysis, Voyles and his collaborators have measured how long it takes, on average, for an atom to gain or lose adjacent atoms as its environment fluctuates in the molten liquid.<\/span><\/p>\n

\u201cAn atom is surrounded by a bunch of other atoms,\u201d Voyles says. \u201cAt really high temperatures, they bounce around and every picosecond (one trillionth of a second), they have a new set of neighbors. As the temperature decreases, they stick with their neighbors longer and longer until they stick permanently.\u201d<\/span><\/p>\n

At high temperatures, the atoms all move fast. Then, as the liquid cools, they move more slowly; a simple description might be that all of the atoms slow down together, at the same rate, until they stop moving and the material becomes a solid glass.<\/span><\/p>\n

\u201cWe have now demonstrated experimentally that is not what happens,\u201d says Voyles.<\/span><\/p>\n

Rather, he says, his team\u2019s experiments confirmed that the time it takes for atoms to lock into place varies widely \u2014 by at least an order of magnitude \u2014 from place to place inside the same liquid.<\/span><\/p>\n

\u201cSome nanometer-sized regions get \u2018sticky\u2019 first and hold on to their neighbors for a very long time, whereas between the sticky bits are bits that are moving much more quickly,\u201d he says. \u201cThey continue to fluctuate 10 times faster than in the slow parts and then everything gets slower, but the sticky parts also get bigger until the sticky parts \u2018win\u2019 and the material becomes a solid.\u201d<\/span><\/p>\n

Now, he and his collaborators are working to understand how the atomic arrangements differ between the slow and fast parts.<\/span><\/p>\n

\u201cThat\u2019s the next big missing piece of the puzzle,\u201d he says.<\/span><\/p>\n

The advance provides valuable information about the fundamental process through which every glass material \u2014 from window glass to plastic bottles to pharmaceutical preparations and many others \u2014 transitions from liquid to solid, says Voyles.<\/span><\/p>\n

\u201cThis is really basic science,\u201d he says. \u201cBut the ultimate potential impact for applications is if we really understand how this works at the atomic level, that gives us the opportunity to build in control that lets us make glasses out of what we want instead of only getting glasses when we get lucky.\u201d<\/span><\/p>\n

Other authors on the paper include Pei Zhang and Jason Maldonis of UW\u2013Madison, and Ze Liu and Jan Schroers of Yale University.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

For millennia, people have used molten sand and other ingredients to create glass and fashion beads, vessels, lenses and windows. These days, metallic glasses \u2014 made entirely of metal atoms \u2014 are being developed for biomedical applications such as extra-sharp surgical needles, stents, and artificial joints or implants because the alloys can be ultra-hard, extra […]<\/p>\n","protected":false},"author":6,"featured_media":10769,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22,17],"tags":[],"class_list":["post-14736","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-other","category-research"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo-150x150.jpg",150,150,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo-300x202.jpg",300,202,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",736,495,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",600,404,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",600,404,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",729,490,false],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",535,360,false],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",95,65,false],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",640,430,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",96,65,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/12\/UW-Madision-logo.jpg",150,101,false]},"author_info":{"info":["Amrita Tuladhar"]},"category_info":"Other<\/a> Research<\/a>","tag_info":"Research","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/14736","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=14736"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/14736\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/10769"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=14736"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=14736"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=14736"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}