Diffraction-based determination of single-crystal elastic constants of polycrystalline titanium alloys.

Alexander Heldmann,Michael Hofmann,Thomas Hansen,Markus Hoelzel,Erika Griesshaber,Norbert Schell,Wolfgang W. Schmahl,Weimin Gan,Winfried Petry

doi:10.1107/s1600576719010720

Abstract

Single-crystal elastic constants have been derived by lattice strain measurements using neutron diffraction on polycrystalline Ti-6Al-4V, Ti-6Al-2Sn-4Zr-6Mo and Ti-3Al-8V-6Cr-4Zr-4Mo alloy samples. A variety of model approximations for the grain-to-grain interactions, namely approaches by Voigt, Reuss, Hill, Kroener, de Wit and Matthies, including texture weightings, have been applied and compared. A load-transfer approach for multiphase alloys was also implemented and the results are compared with single-phase data. For the materials under investigation, the results for multiphase alloys agree well with the results for single-phase materials in the corresponding phases. In this respect, all eight elastic constants in the dual-phase Ti-6Al-2Sn-4Zr-6Mo alloy have been derived for the first time.

Highlights

Single-crystal elastic constants are essential material parameters in fundamental materials science as well as in engineering
The elastic properties of any polycrystalline bulk material are based on its single-crystal elastic constants
A variety of micromechanical models have been established to describe the relations between the elastic properties of a polycrystalline bulk material and the singlecrystal elastic constants, the most common applied approaches being those introduced by Voigt (1928), Reuss (1929), Hill (1952), Kroener (1958), de Wit (1997) and Matthies et al (2001)

Summary

Introduction

Single-crystal elastic constants are essential material parameters in fundamental materials science as well as in engineering. The elastic properties of any polycrystalline bulk material are based on its single-crystal elastic constants. A variety of micromechanical models have been established to describe the relations between the elastic properties of a polycrystalline bulk material and the singlecrystal elastic constants, the most common applied approaches being those introduced by Voigt (1928), Reuss (1929), Hill (1952), Kroener (1958), de Wit (1997) and Matthies et al (2001). Lattice strains and stresses are related by the diffraction elastic constants (DECs), which depend on the direction in the crystal as described by the lattice planes (hkl) of the corresponding Bragg reflections. DECs in turn are based on the single-crystal elastic constants. Knowledge of the single-crystal elastic constants is essential for diffraction-based stress analysis

Methods

Results

Conclusion