Diffraction and single-crystal elastic constants of Inconel 625 at room and elevated temperatures determined by neutron diffraction

An acoustic time of flight technique is described in detail for measuring the elastic constants of cubic single crystals that allows for the constants to be determined at elevated temperature. Although the overall technique is not new, various aspects of the present work may prove extremely useful to othersinterested in finding these values, especially for aerospace materials applications. Elastic constants were determined for the nickel based alloy, Hastelloy X from room temperature to 1000°C. Accurate elastic constants were needed as part of an effort to predict both polycrystal mechanical properties and the nature of grain induced heterogeneous mechanical response. The increased accuracy of the acoustically determined constants resulted in up to a 15 percent change in the predicted stresses in individual grains. These results indicate that the use of elastic single crystal constants of pure nickel as an approximation for the constants of gas turbine single crystal alloys, which is often done today, is inaccurate.

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Verification of the elastic constants for α-Al2O3using high-resolution neutron diffraction

Journal of Applied Crystallography ◽

10.1107/s0021889810049046 ◽

2010 ◽

Vol 44 (1) ◽

pp. 216-218 ◽

Cited By ~ 5

Author(s):

Erich H. Kisi ◽

Christopher J. Howard ◽

Jianfeng Zhang

Keyword(s):

High Resolution ◽

Neutron Diffraction ◽

Single Crystal ◽

Elastic Constants ◽

Diffraction Method ◽

Polycrystalline Sample ◽

Lattice Strains ◽

Recent Suggestion

Precise lattice strains measured using high-resolution neutron diffraction from a solid polycrystalline sample are used to explore the single-crystal elastic constants of α-Al2O3(corundum). The analysis confirms a recent suggestion that, contrary to the long-accepted view, the sign ofs14should be negative. It also indicates that the magnitude ofs13should be adjusted from −0.38 × 10−12to −0.47 × 10−12 Pa−1. It is found that, micromechanically, the polycrystal responds to stress in a manner very close to the Reuss limit. The results confirm the applicability of the diffraction method, which could prove useful when other techniques give ambiguous results.

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Neutron diffraction intensity enhancement of ∝-LiIO3 single crystal under DC voltage at elevated temperatures

Solid State Communications ◽

10.1016/0038-1098(89)90834-x ◽

1989 ◽

Vol 69 (3) ◽

pp. 201-202 ◽

Cited By ~ 1

Author(s):

Yang Zhen ◽

Cheng Yu-fen

Keyword(s):

Neutron Diffraction ◽

Single Crystal ◽

Elevated Temperatures ◽

Diffraction Intensity ◽

Dc Voltage ◽

Intensity Enhancement

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Single Crystal Elastic Constants of the MAX Phase Ti3AlC2 Determined by Neutron Diffraction

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.2417 ◽

2010 ◽

Vol 638-642 ◽

pp. 2417-2422 ◽

Cited By ~ 1

Author(s):

Oliver Kirstein ◽

Jian F. Zhang ◽

Erich H. Kisi ◽

D.P. Riley ◽

M.J. Styles ◽

...

Keyword(s):

Neutron Diffraction ◽

Single Crystal ◽

Elastic Constants ◽

Compressive Load ◽

Polycrystalline Sample ◽

Max Phase ◽

Unit Cell Parameters ◽

Cell Parameters ◽

Diffraction Peaks ◽

Good Agreement

The ternary ceramic Ti3AlC2 has an interesting combination of electrical, thermal and mechanical properties. Single crystal elastic constants under the Reuss approximation for the micromechanical state were obtained by analysing the shifts of neutron diffraction peaks while a polycrystalline sample was subjected to a compressive load varying from 5 to 300 MPa. The values of Young’s modulus and Poisson’s ratio computed from the single crystal compliances are in good agreement with those obtained directly from strain gauges and from the average changes in the a and c unit cell parameters.

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Evaluation of single crystal elastic constants and stacking fault energy in high-nitrogen duplex stainless steel by in-situ neutron diffraction

Scripta Materialia ◽

10.1016/j.scriptamat.2016.03.013 ◽

2016 ◽

Vol 119 ◽

pp. 1-4 ◽

Cited By ~ 14

Author(s):

Yanghoo Kim ◽

Yong Min Kim ◽

Ji-Yeon Koh ◽

Tae-Ho Lee ◽

Wan Chuck Woo ◽

...

Keyword(s):

Stainless Steel ◽

Neutron Diffraction ◽

Single Crystal ◽

Duplex Stainless Steel ◽

Elastic Constants ◽

Stacking Fault ◽

Stacking Fault Energy ◽

High Nitrogen ◽

In Situ Neutron Diffraction

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Measurement of single-crystal elastic constants by neutron diffraction from polycrystals. Addendum and erratum

Journal of Applied Crystallography ◽

10.1107/s0021889899016441 ◽

2000 ◽

Vol 33 (2) ◽

pp. 418-418 ◽

Cited By ~ 1

Author(s):

C. J. Howard ◽

E. H. Kisi

Keyword(s):

Neutron Diffraction ◽

Single Crystal ◽

Elastic Constants

Correction is made to an equation in a paper by Howard & Kisi [J. Appl. Cryst.(1999),32, 624–633] and additional references are cited.

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Measurement of single-crystal elastic constants by neutron diffraction from polycrystals

Journal of Applied Crystallography ◽

10.1107/s0021889899002393 ◽

1999 ◽

Vol 32 (4) ◽

pp. 624-633 ◽

Cited By ~ 35

Author(s):

C. J. Howard ◽

E. H. Kisi

Keyword(s):

Neutron Diffraction ◽

Single Crystal ◽

Elastic Constants ◽

Tetragonal Zirconia ◽

Uniaxial Stress ◽

Polycrystalline Materials ◽

Transformation Toughening ◽

Reflection Index ◽

Higher Symmetry ◽

The Given

The relationships of diffraction averaged elastic compliances for an ideally random polycrystal to the single-crystal elastic compliances are given, within the Reuss approximation, for crystal systems with orthorhombic and higher symmetry. For anisotropic materials, these diffraction elastic compliances are dependent on the reflection indexhkl. Expressions for the conventional elastic constants (Young's modulus, Poisson's ratio) are also given. A connection is made to the `X-ray elastic constants' used for diffraction-based measurements of residual stress. The relationships are used to calculate diffraction averaged constants for comparison with neutron diffraction data recorded from samples under applied uniaxial stress. The Reuss approximation works well for materials with the capacity for plastic deformation, such as metals and transformation toughening ceramics, whereas for other materials the Voigt–Reuss–Hill approximation gives better results. Based on the given relationships and experimental determinations of the diffraction elastic compliances for polycrystalline materials, a method is developed for determining the single-crystal elastic constants. The method for estimating single-crystal compliances is demonstrated here by application to extant data on Ni–Cr–Fe and Ti–6 wt% Al–4 wt% V alloys, and new measurements on cubic zirconia. It has been applied very recently [Kisi & Howard (1998).J. Am. Ceram. Soc.81, 1682–1684] to determine the previously unknown elastic constants for a tetragonal zirconia.

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Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009292x ◽

1976 ◽

Vol 34 ◽

pp. 592-593

Author(s):

Ernest L. Hall ◽

J. B. Vander Sande

Keyword(s):

Mechanical Properties ◽

Single Crystal ◽

Dislocation Structure ◽

Room Temperature ◽

Elevated Temperatures ◽

Strain Curve ◽

Optical Devices ◽

Semiconductor Compound ◽

Wide Range ◽

Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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