Forge-Hardened TiZr Null-Matrix Alloy for Neutron Scattering under Extreme Conditions

Abstract

For neutron scattering research that is performed under extreme conditions, such as high static pressures, high-strength metals that are transparent to the neutron beam are required. The diffraction of the neutron beam by the metal, which follows Bragg's law, can be completely removed by alloying two metallic elements that have coherent scattering lengths with opposite signs. An alloy of Ti and Zr, which is known as a TiZr null-matrix alloy, is an ideal combination for such purposes. In this study, we increased the hardness of a TiZr null-matrix alloy via extensive mechanical deformation at high temperatures. We successfully used the resulting product in a high-pressure cell designed for high-static-pressure neutron scattering. This hardened TiZr null-matrix alloy may play a complementary role to normal TiZr alloy in future neutron scattering research under extreme conditions.

Metals Challenged by Neutron and Synchrotron Radiation

“…Interestingly, the scattering process of the titanium-zirconium null-matrix material produced by Okuchi et al [12] relates to the investigations summarized by Erdely et al [8], because titanium-aluminides equally form a null-matrix when fully disordered. In their study, the authors use the latter to determine the aforementioned crystallographic order parameter upon disorder, rounding up this section.…”

“…Related to this topic is the making of a titanium-zirconium null-matrix material, reported by Okuchi et al [12], which is being developed as a neutron-transparent material for gaskets and high-pressure cells in neutron scattering experiments under extreme conditions, as outlined above. In a null-matrix material, coherent neutron scattering is suppressed by alloying elements of positive and negative scattering amplitude, Zr and Ti, respectively, in a solid solution.…”

Thermal deflection in neutron scattering sample environments at Oak Ridge National Laboratory

“…For instance, vanadium has a near-zero coherent scattering cross section near the elastic line, while a null matrix alloy like Ti 67.6 Zr 32.4 can exhibit zero bragg peaks. 11,12 In the standard vacuum furnace used at the SNS, 4 the sample is mounted to a long niobium stick, with the support flange positioned at the top of the sample stick [Fig. 1(c)].…”