Scientists have discovered that copper melts gradually rather than collapsing all at once under extreme heat. The finding challenges earlier computer models that predict how nuclear fusion reactor materials handle extreme thermal loads.<\/p>\n
The study<\/a> was published in Nature Communications. It was led by researchers at the Department of Energy\u2019s SLAC National Accelerator Laboratory, working alongside teams from several European universities.<\/p>\n Standard materials testing often uses a \u201ccook and look\u201d method. Researchers blast a sample with extreme heat and inspect the melted residue after it cools. However, this approach leaves only a metallic puddle, making it impossible to see the step-by-step physical changes that occur during heating.<\/p>\n To solve this problem, the team used SLAC\u2019s MeV-UED instrument. This electron camera can track atomic movements down to the femtosecond, which is one quadrillionth of a second.<\/p>\n The researchers hit a thin copper film with laser heat to trigger rapid temperature increases. \u201cThey blasted a thin copper film with laser heat, then sent an electron beam to image the sample as it heated,\u201d said an SLAC press release. \u201cWhat they saw surprised them.\u201d<\/p>\n Defying predictions at superheating limit<\/p>\n Past computer models predicted a very different outcome for copper during rapid heating<\/a>. According to these simulations, the sample would start melting at its surfaces around 1,085\u00b0C (1,985\u00b0F).<\/p>\n \u201cThe sides and edges would continue melting with increasing temperature, while the central area of the sample, which is subject to higher pressures, would retain its crystal lattice structure for longer,\u201d explained the press release.<\/p>\n Those simulations indicated that once the core reached about 1,424\u00b0C (2595.2\u00b0F)\u2014roughly 1.25 times the normal melting point\u2014the remaining crystal structure would suddenly break down into liquid. This point is known as copper\u2019s superheating limit.<\/p>\n Instead, the real-time images revealed that copper retained order in its crystal lattice and melted steadily past this theoretical limit. The experiments also detected pre-melting, where atomic disorder formed along nanoscale grain boundaries before the metal reached its standard melting point<\/a>.<\/p>\n The team discovered why older computer simulations failed to match the experiment. Computer models often use assumptions to manage complex atomic calculations. \u201cIn this case, existing simulations had assumed the melting copper would face static conditions, with uniform pressure on all sides keeping the atoms fixed in place,\u201d noted the researchers.<\/p>\n Refining simulations for fusion energy applications<\/p>\n In reality, the experiment involved dynamic pressure conditions. These dynamic conditions allowed the copper atoms to relax and shift, which helped the material retain structural order past the superheating limit. Once scientists included these dynamic conditions in their computer calculations, the simulation results matched the experimental data.<\/p>\n \u201cThis is a major improvement to modeling capabilities and their predictive power going forward,\u201d said Siegfried Glenzer, High Energy Density Science division director. \u201cThe precision and resolution with which we are able to see these things demonstrates how remarkable this technique is at unveiling these ultrafast, ultrasmall dynamics.\u201d<\/p>\n These findings will directly support the development of future fusion power plants. Fusion reactors aim to recreate the energy processes of stars. While the core plasma reaches hundreds of millions of degrees, the components surrounding the chamber must endure sudden, extreme heat spikes similar to spacecraft entering Earth\u2019s atmosphere.<\/p>\n Engineers use computer models and artificial intelligence to screen materials for these harsh environments. \u201cWith a stronger grasp on copper\u2019s behavior, they plan to study the more complex dynamics of copper alloys and their potential for absorbing heat in fusion systems,\u201d concluded<\/a> the press release.<\/p>\n The SLAC-led team now plans to test copper under balanced pressure conditions. They will also use their electron imaging method to study more complex copper alloys.<\/p>\n","protected":false},"excerpt":{"rendered":"Scientists have discovered that copper melts gradually rather than collapsing all at once under extreme heat. The finding…\n","protected":false},"author":3,"featured_media":1003169,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[8],"tags":[26817,2096,26260,63551,159,67,132,68],"class_list":["post-1003168","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-copper","tag-heat","tag-nuclear-fusion","tag-nuclear-reactor","tag-science","tag-united-states","tag-unitedstates","tag-us"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/117101726618693606","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/1003168","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=1003168"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/1003168\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/1003169"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=1003168"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=1003168"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=1003168"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}