March_2022_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 2 1 1 do so while they’re still inside a working battery for themost realistic picture yet. slac.stanford.edu . MELTING DYNAMICS DISCOVERY A research team led by associ- ate professor Byoung Ick Cho from the Gwangju Institute of Science and Tech- nology (GIST), Korea, studied the warm dense matter state for copper created by using intense laser pulses. The opti- cal pulse excitation created copper elec- trons with a temperature of ~20,000 K, which is similar to that of a giant planet’s core. Then, right when the copper sam- ple was about to melt, the researchers took snapshots of the electrons using ultrafast x-ray pulses from an x-ray free electron laser. This allowed them to analyze what happens in noble metals, such as copper, when their bonding electrons are highly excited and the metals are about to melt. Notably, when heated quickly, the bonds between copper atoms first hardened for about one trillionth of a second before melting. The team car- ried out detailed theoretical analysis backed by simulations, which revealed that while some electrons were excited to higher energies at such high tem- peratures, some experienced a stronger attraction toward the nucleus. These findings could have applications in con- texts where materials are subjected to extremely high pressures and tempera- tures. “By capturing theprecisemoment when a material starts to melt or vapor- ize, we can generate new phases of mat- ter or energy, which would be relevant to fields such as fusion, laser machin- ing, and even nanosurgery,” speculates Cho. www.gist.ac.kr/en. Femtosecond x-ray snapshots of warm dense copper electrons can reveal elusive phenomena predicted over a decade ago. Courtesy of GIST. ASM HANDBOOK VOLUMES 2A & 2B ALUMINUM SET asminternational.org PURCHASE THIS TWO-VOLUME SET AT A SPECIAL DISCOUNTED PRICE! The set includes ASM Handbooks, Volume 2A: Aluminum Science and Technology and Volume 2B: Properties and Selection of Aluminum Alloys .