title: Time- and angle-resolved x-ray diffraction to probe structural and chemical evolution during Al-Ni intermetallic reactions.
abstract: We present novel time- and angle-resolved x-ray diffraction (TARXD) capable of probing structural and chemical evolutions during rapidly propagating exothermic intermetallic reactions between Ni-Al multilayers. The system utilizes monochromatic synchrotron x-rays and a two-dimensional (2D) pixel array x-ray detector in combination of a fast-rotating diffraction beam chopper, providing a time (in azimuth) and angle (in distance) resolved x-ray diffraction image continuously recorded at a time resolution of ~30 μs over a time period of 3 ms. Multiple frames of the TARXD images can also be obtained with time resolutions between 30 and 300 μs over three to several hundreds of milliseconds. The present method is coupled with a high-speed camera and a six-channel optical pyrometer to determine the reaction characteristics including the propagation speed of 7.6 m/s, adiabatic heating rate of 4.0 × 10(6) K/s, and conductive cooling rate of 4.5 × 10(4) K/s. These time-dependent structural and temperature data provide evidences for the rapid formation of intermetallic NiAl alloy within 45 μs, thermal expansion coefficient of 1.1 × 10(-6) K for NiAl, and crystallization of V and Ag(3)In in later time.
authors: Department of Chemistry, Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA. csyoo@wsu.edu
authors: Choong-Shik
authors: CS
authors: Yoo
authors: Haoyan
authors: H
authors: Wei
authors: Jing-Yin
authors: JY
authors: Chen
authors: Guoyin
authors: G
authors: Shen
authors: Paul
authors: P
authors: Chow
authors: Yuming
authors: Y
authors: Xiao