Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

Abstract

A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C.

The Effects of Deformation on the Early Crystallization Kinetics of Basaltic Magmas

“…In order to study the effects of deformation on the crystallization of magmas, we used a high temperature deformation apparatus developed at the Advanced Light Source, Lawrence Berkeley National Laboratory (Figure 1). This hot cell has been designed to image samples using X-ray micro-tomography during mechanical loading (maximum force of 2.2 kN) at temperatures up to 2300 • C (Haboub et al, 2014). Six infrared halogen lamps are symmetrically arranged to focus light, and thus heat, in the central part of the chamber, where samples are held between two water-cooled grippers.…”

“…Drawing showing the deformation apparatus developed byHaboub et al (2014). (a) Complete view of the apparatus placed on a rotation and translation stage for X-ray micro-tomography.…”

“…(c) View of six halogen lamps positioned around the heating chamber. Reprinted fromHaboub et al (2014), with the permission of AIP Publishing.…”

Mapping local deformation behavior in single cell metal lattice structures

“…Several studies have used tensile testing during X-ray tomography to map void growth in heterogeneous ductile materials, such as dual phase steels [31] and Ti6Al4V [32]. At the Advanced Light Source's (ALS, LBNL, Berkeley, CA) tomography beamline (8.3.2) there is a dedicated custom built mechanical testing device developed by Haboub et al [33] and Bale et al [34] that can test structures in both compression or tension. The high flux achieved at synchrotron facilities enables in-situ mechanical testing to take place over only a few hours, while lab based tomography systems would take a prohibitively long time to acquire the necessary timesteps required during loading.…”

Synchrotron X-ray micro-tomography at the Advanced Light Source: Developments in high-temperature in-situ mechanical testing

“…Uniaxial loading tests of such materials, particularly tensile testing of CMCs has been and continues to be a highly successful part of the 8.3.2. user program [3]. Over the past several years, the majority of mechanical testing on 8.3.2 has been performed using a high temperature loading cell described in detail in reference [4] and shown in Figure 1. To address growing scientific needs, we are developing new in-situ mechanical testing capabilities to include in-situ tensile testing with acoustic emission analysis in addition to flexural testing with both 3-point and 4-point bending.…”