実験報告書様式（一般利用課題・成果公開利用）

MLF Experimental Report

提出日 Date of Report
01/07/2011

課題番号 Project No.

装置責任者 Name of responsible person

2009B0042

Kazuya Aizawa

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Local Crystal Rotation and Misfit Strain after High Temperature

TAKUMI/(BL 19)

Creep in a Single-Crystal Nickel-Base Superalloy

実施日 Date of Experiment

実験責任者名 Name of principal investigator

09-10/05/2010

Yoshinori Shiota
所属 Affiliation
Japan Atomic Energy Agency
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
Name of sample : Single-crystal nickel-base superalloy (TMS-75)
Chemical formula : γ (Ni) matrix and γ’ (Ni3Al) coherent precipitate phase
Compositions (atomic%) : Ni 63.0, Al 13.7, Co 12.6, Cr 3.6, Ta 2.1, W 2.0, Re 1.66, Mo 1.3, Hf 0.03
Physical form : Tensile bar with uniform deformation part of 4mm(R) x 20mm(L)State of sample : After high temperature creep test that is 200hr-creep time deformation with 137MPa at1100degrees C.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

[ Experimental method ]The relative sample of single-crystal nickel-base superalloy was set up horizontally in penta-axial goniometeron the TAKUMI sample stage. The angle between scattering direction and incident neutron beam was 45 degree.
Because the sample was single crystal as γ and γ’ phases with same crystal orientation, the lattice planes (h00),(0k0) and (00l) of two phases were measured at same time. Neutron gauge volume was selected as 1x1x1mm3 at
south detector bank by using small radial collimator. The scanning steps were 13 points along axial direction in
the sample. Measured neutron diffraction data was converted into two forms. One form was profile data (2D:TOF and Intensity) from total channel. Another one was pixel data (3D: TOF, Intensity and Pixel) from channelby channel.
[ Results ]Different with previous experiments based on the average information on the entire sample, the local crystal
rotation and misfit strain measurement was evaluated in this experiment by high-spacial resolution neutron
diffraction to clarify the mechanism of the creep damage evolution.
12. 実験方法及び結果（つづき） Experimental method and results (continued)
Considering that the high-temperature creep deformation may result in the local crystal rotation of γ/γ’ phases at
one domain position, the local crystal rotation of a super-alloy specimen after 200hours creep deformed at 1373K
was measured. Fig. 1(a) explained how the pixel information of time-of-flight neutron diffraction spectra wasemployed to describe the local orientation of γ/γ’ phases of super-alloy, while Fig. 1(b) summarized all the local
crystal orientations observed from different pixels on detector. Here, a small change in thecrystallographic orientation of monocrystalline was found by seeing the diffraction information
separately by each pixel of the detector. The initial crystal orientation was straight line (χ is zero) before
creep deformation, while the local crystal orientation rotation rotated gradually in proportion to the creep
deformation, and the microcracks initiated in the deformation region before rupture. The local creep deformation
was caused by the accumulation of slip deformation. Therefore, the distributions of local crystal orientations ofthe γ and γ’ phases by neutron diffraction can then be measured to evaluate damage process in a non-destructive
method, and to provide quantitative information for predicting the lifetime of Ni-base superalloy parts. At thesame time, the misfit strain (=2(aγ’-aγ)/(aγ’+aγ)) between the γ matrix and the γ’ phase was evaluated as amicrostructural deformation parameter, related to the local crystal rotation. However, only one sample wasmeasured after creep deformation, and the relation between the local crystal rotation and the misfit was not clear.
Therefore, in-situ evaluation of high temperature creep deformation behavior is necessary to clarify themechanism of the creep damage evolution. At TAKUMI/J-PARC, the device performance including optional
environment and the neutron beam intensity have enough ability for this in-situ measurement, and we areplanning next experiment.

Figure 1 Experimental results about local crystal rotation of Ni-base superalloy after 1100degreeC-200hr creep
test obtained from TAKUMI neutron diffraction.
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