Lattice dynamics of the high temperature shape memory alloy Nb-Ru

G. Gu; G. Xu; J. Gardner; R. W. Fonda; S. M. Shapiro

REVIEW

Lattice dynamics of the high temperature shape memory alloy Nb-Ru

S. M. Shapiro, G. Xu, G. Gu, J. Gardner, R. W. Fonda

Materials Science · Submitted 1 Mar 2006 · 27 references

Pith's verdict: First single-crystal neutron data on Nb-Ru show broad TA2 softening, but the second-order claim hinges on an underdetermined three-point extrapolation.

T0 · AI review

How this review was made: An AI referee (deepseek-v4-flash) read the paper on August 28, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

T0 AI review An AI read the paper and answered a fixed list of questions.
T1 Audit Automatic checks that the references and files the paper relies on exist and match.
T2 Compute The paper's code or calculations re-run with the same results.
T3 Formal statement The claims written out in a formal math language a computer can read.
T4 Proof Those claims proved, and the proof checked by computer.

How Pith checks papers →

· 4 major objections · 4 minor · Ask about this paper · The compiled record · Read the full review →

Challenge this review Comment (0) Read on arXiv ↗

Cite ▾

arXiv IDcond-mat/0603031 (version 1)

Pith IDQFQQSTL4, Pith's permanent record of this paper and its review

CitationG. Gu, G. Xu, J. Gardner, R. W. Fonda, S. M. Shapiro. "Lattice dynamics of the high temperature shape memory alloy Nb-Ru." arXiv:cond-mat/0603031 (2006). https://pith.science/paper/QFQQSTL4

Cite this reviewBibTeX for Pith's review of this paper

Claim paper

Why Pith says this

Highlight any text to comment on it.

Editor's note

read the letter

First, the headline: this is the first single-crystal neutron scattering study of Nb-Ru, and the data are worth having. The authors grew a crystal, confirmed the CsCl structure by seeing the weak (1,0,0) superlattice reflection, measured phonon dispersion along [100] and [110], and extracted elastic constants. The main experimental result is clean: the [110]-TA2 branch softens over most of the Brillouin zone as the martensitic transition is approached, with no q-specific anomaly and no lattice modulation. That is a solid empirical contribution.

The soft spot is the interpretation. The claim that the β→β' transition is second order rests on Fig. 6 and Fig. 7: linear fits of ω² vs T for three q-values (0.1, 0.15, 0.2), with no error bars, and then a linear extrapolation of the fitted intercepts T_E(q) down to q=0, giving 892°C, close to TM≈900°C. That is a thin chain. The paper itself notes the branch never actually reaches zero at any measured temperature. The transition is observed to be abrupt over <10°C, and prior reports describe first-order behavior with small hysteresis and even a 200°C coexistence range. So the assertion that C' vanishes at TM goes beyond what the data support. A direct measurement of C' near TM, or of the q→0 sound velocity, would settle it.

I'm not saying the second-order scenario is wrong—it might be right, and the near-zero hysteresis and the extrapolation landing close to TM are suggestive. But the evidence is not sufficient to state it as a conclusion. The paper would be stronger if it presented the extrapolation as a hypothesis and clearly flagged the need for elastic constant measurements near TM. To their credit, the authors do note that no such measurements exist and suggest they be performed, so they are not hiding the gap.

Who is this for? Researchers working on martensitic transformations, phonon softening, and high-temperature shape memory alloys. The phonon data and elastic constants are a useful reference point. I'd send it to peer review—it deserves a serious referee even if the interpretive claim needs to be dialed back. I would probably cite it for the experimental data, not for the second-order conclusion.

Referee report

Significance

If the central claim is correct, the paper provides a rare and important example of a martensitic transformation driven by complete softening of a shear phonon branch, with C' vanishing at the transition temperature. The experimental data are novel: these are the first single-crystal phonon measurements on Nb-Ru, and the observation of a temperature-dependent softening extending over most of the Brillouin zone is a significant contribution to the study of shape-memory alloys. The paper also contains a useful confirmation of the high-temperature CsCl structure. However, the quantitative conclusion of a second-order transition rests on a chain of extrapolations from only three q-points, with no reported uncertainties and no direct q=0 elastic measurement, so the paper as written supports a suggestive rather than conclusive case.

Major objections (4)

[Section 'Temperature dependent phonon branches', Fig. 6] The linear fits of (ħω)² vs T for q=0.1, 0.15, and 0.2 are presented without error bars on the phonon energies, without the number of data points per fit, and without goodness-of-fit statistics. Since the extrapolated zero-energy temperatures TE(q) are the foundation of the entire second-order claim, the authors should report the fitted parameters with uncertainties, show the residuals, and state the statistical quality of each linear fit.
[Fig. 7 and Discussion, final paragraph] The q→0 extrapolation uses only three q-values and assumes that TE(q) is linear in q over the range [0.1, 0.2]. No physical justification for this linearity is provided, and the three points are not shown with any uncertainty; a modest quadratic term or a different low-q behavior could shift the intercept TE(q=0)=892°C by tens of degrees. The authors should either justify the linear form with a model or provide a robustness analysis showing how the intercept changes under reasonable alternative fits.
[Discussion, paragraph 4 and Fig. 5] The text acknowledges that the measured phonon energies never approach zero at any temperature (Fig. 5), and the fitted TE(q) values lie well below the measured temperature range. The classical soft-mode relation ω²∝(T−TE) is assumed to hold from the measured high-temperature region down to TM, but the β→β' transition is observed to be abrupt over <10°C (Fig. 2). A direct measurement of C' or of the [110]-TA2 sound velocity at q→0 approaching TM, or at least a measurement of a lower-q phonon closer to TM, is needed to determine whether the softening actually reaches zero or is interrupted by a first-order transition.
[Discussion, final paragraph versus Introduction and Fig. 2] The conclusion that the β→β' transition is second order is in tension with the paper's own observation that the transition is abrupt over <10°C with very little hysteresis, and with earlier reports cited in the Introduction that describe the transition as first order with possible phase coexistence over a 200°C range. The authors should explicitly address how a second-order transition can be reconciled with the observed abruptness and with previous thermodynamic characterizations, and should clarify what new evidence specifically rules out a first-order transition with a strongly softened but finite C' at TM.

Minor objections (4)

[Throughout] There are several typographical errors in the text and references, including "transtion" in the Discussion, "NbTu4,5" in the Introduction, "Acata Met." in Ref. 11, "Heidleburg" in Ref. 9, and "Scientifi American" in Ref. 1; these should be corrected.
[Table I] The caption lists the β-phase lattice parameter as measured at "900K," whereas the text reports measurements at 900°C; this appears to be a typo and should be corrected.
[Results, Phase transformations, and Discussion] The text states in the Results that a feature appears near 800°C on heating and near 700°C on cooling for the β'→β'' transition, but the Discussion reports the transition at ~800°C on cooling and ~725°C on heating; these statements are inconsistent and should be reconciled.
[Fig. 7] The figure is small, and the three data points are not individually labeled with their q values or any uncertainty estimates; adding labeled points with error bars would greatly improve the reader's ability to judge the extrapolation.

How Pith checks papers → · Full audit of this paper →

The paper

The paper claims

The paper claims that in Nb-Ru the [110]-TA2 phonon branch softens progressively with decreasing temperature and that its squared energy extrapolates to zero at 892°C, essentially the martensitic transition temperature, implying that the…

The reading

This paper reports the first single-crystal neutron scattering study of the high-temperature shape memory alloy Nb50Ru50 and argues that its martensitic transformation is continuous rather than classically first order. The measured [110]-TA2 transverse acoustic phonon, which in the long-wavelength limit is the shear elastic constant $C'=(C_{11}-C_{12})/2$, softens over nearly the whole Brillouin zone as the transition near 900°C is approached. Squared phonon energies at three low wavevectors extrapolate linearly to zero at temperatures $T_E(q)$, and $T_E(q)$ itself extrapolates linearly to 892°C at $q=0$. The paper concludes that $C'$ would vanish at the transformation and that the β-to-β' transition is second order, with no additional lattice modulation in the cubic phase. A reader should care because Nb-Ru is a candidate for high-temperature shape memory applications, and the mechanism matters for predicting how the transformation responds to stress, composition, and thermal cycling.

What carries the argument

The central object is the [110]-TA2 transverse acoustic phonon, a shear wave propagating along [110] with atomic displacements along [1-10]; its zone-center limit defines the elastic constant $C'=(C_{11}-C_{12})/2$. The argument's engine is the classical soft-mode scaling relation $\omega^2 \propto (T - T_E)$ from the theory of structural phase transitions. Linear fits of squared phonon energy against temperature at fixed $q$ give zero-energy intercepts $T_E(q)$; plotting those intercepts against $q$ and extrapolating to $q=0$ turns a handful of phonon measurements into a prediction for the macroscopic shear modulus at the transition. The comparison cases discussed in the paper, including invar-type Fe-Pd alloys and pre-martensitic systems, define what is absent in Nb-Ru: no finite-$q$ anomaly, no lattice modulation, and softening throughout the branch rather than at a special wavevector.

Extended reading notes

Core claim

The discovery is that the β-to-β' martensitic transformation in Nb-Ru is driven by a homogeneous shear instability of the parent cubic phase. Inelastic neutron scattering on a single crystal shows that the [110]-TA2 branch, corresponding in the $q\to 0$ limit to $C'=(C_{11}-C_{12})/2$, softens progressively over roughly 80% of the Brillouin zone as temperature decreases from 1550°C toward the transformation temperature. At three low wavevectors, $(\hbar\omega)^2$ is linear in temperature and extrapolates to zero at finite temperatures; those zero-energy temperatures are linear in $q$ and reach 892°C at $q=0$, close to the measured transition temperature. The paper states that this implies the β-to-β' transition is second order and that the elastic constant $C'$ goes to zero at the transition, unlike a classic first-order martensite in which the soft mode stays finite at the transition temperature. It also reports no pre-martensitic modulation and only weak softening of the branch associated with $C_{44}$.

Load-bearing premise

The load-bearing premise is that the squared phonon energy stays linear in temperature all the way to the transition and that the zero-energy temperatures of the three measured wavevectors lie on a straight line in $q$, so the $q=0$ intercept of 892°C is trustworthy.

Editorial extensions

If this is right

Direct elastic measurements should show $C'(T)$ falling toward zero near 892°C, with $C_{11}-C_{12}$ softening dramatically while $C_{44}$ remains comparatively stiff.
The β-to-β' transformation should be accompanied by very small or zero latent heat and negligible hysteresis, since the transformation is proposed to be continuous rather than classically first order.
Because there is no finite-wavevector precursor, no pre-martensitic modulated phase is expected; the only precursor should be diffuse scattering very close to the Bragg peak, growing as the transition is approached.
The mechanism points toward electronic degrees of freedom as the driver of the softening, so first-principles calculations of the electronic structure and electron-phonon coupling should reproduce the whole-branch softening and the $q$-dependent zero-energy temperatures.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

Not stated in the paper: the linear $T_E(q)$ relation can be tested at smaller wavevectors, such as $q=0.05$, or by measuring $C'(T)$ directly; a deviation from linearity would move the $q=0$ intercept away from 892°C and reopen the first-order question.
Not stated in the paper: if the transition is truly second order, applied uniaxial stress, which couples linearly to shear strain, should shift the transformation temperature through its effect on $C'$, and the shift should follow the same linear softening curve, an experimentally checkable consequence.
Not stated in the paper: the same whole-branch softening without a finite-$q$ anomaly may occur in the closely related equiatomic Ta-Ru alloy, which undergoes the same type of β-to-β' transformation; neutron measurements there could show whether the linear $T_E(q)$ intercept is a general feature of this alloy family.
Not stated in the paper: an ideal second-order elastic shear instability implies that the cubic phase becomes mechanically unstable with respect to the [110] shear exactly at the transformation temperature, which could make the measured transition temperature sensitive to impurities and small stoichiometry variations.

Original abstract

Nb-Ru is a high temperature shape memory alloy that undergoes a Martensitic transformation from a parent cubic b-phase into a tetragonal b' phase at TM 900 C. Measurements of the phonon dispersion curves show that the [110]-TA2 phonon branch, corresponding in the q=0 limit to the elastic constant C'=1/2(C11-C12) has an anomalous temperature dependence. Nearly the entire branch softens with decreasing temperature as TM is approached. The temperature dependence of the low-q phonon energies suggests that the elastic constants would approach 0 as T approaches TM, indicating a second order transition. No additional lattice modulation is observed in the cubic phase.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 4,268 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.02 · states limitation 0.17 · human participants 0.02 · controlled comparison 0.03 · randomized assignment 0.01 · states quantitative result 0.91 · compares with prior results 0.05 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; show every role.

Nb-Ru is a high temperature shape memory alloy that undergoes a Martensitic transformation from a parent cubic b-phase into a tetragonal b' phase at TM 900 C. Measurements of the phonon dispersion curves show that the [110]-TA2 phonon branch, corresponding in the q=0 limit to the elastic constant C'=1/2(C11-C12) has an anomalous temperature dependence. Nearly the entire branch softens with decreasing temperature as TM is approached. The temperature dependence of the low-q phonon energies suggests that the elastic constants would approach 0 as T approaches TM, indicating a second order transition. No additional lattice modulation is observed in the cubic phase.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	Nb-Ru is a high temperature shape memory alloy that undergoes a Martensitic transformation from a parent cubic b-phase into a tetragonal b' phase at TM 900 C.	background 0.98	0.23	0.07	asserted 1.00
s1	Measurements of the phonon dispersion curves show that the [110]-TA2 phonon branch, corresponding in the q=0 limit to the elastic constant C'=1/2(C11-C12) has an anomalous temperature dependence.	result 0.96	0.88	0.12	asserted 1.00
s2	Nearly the entire branch softens with decreasing temperature as TM is approached.	result 1.00	0.82	0.13	asserted 1.00
s3	The temperature dependence of the low-q phonon energies suggests that the elastic constants would approach 0 as T approaches TM, indicating a second order transition.	interpretation 0.99	0.80	0.58	hedged possibility 1.00
s4	No additional lattice modulation is observed in the cubic phase.	result 1.00	0.86	0.05	asserted 1.00

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from observation or experiment 1.00.

What was examined, and what was not

sources read

arXiv listing abstract v1

not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

not run

S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

References

Works cited (27)

[110]

60.9 11.6 TABLE III Elastic Constants (Measured at 1100°C) Elastic Constant 1011 dynes/cm2 C11 20.7 C44 3.9 C’=1/2(C11-C12) 0.81 C12 19.1 14 Figure 1 15 Figure 2. 16 Figure 3 17 Figure 4 18 0 1 2 3 4 5 0 0.05 0.1 0.15 0.2 NbRu [qq0]-TA2910°C 950°C 1000°C 1100°C 1250°C 1550°C Energy (meV) [qq0] Figure 5 19 Figure 6. 20 0 200 400 600 800 1000 0 0.050.10.150...

View on Pith
[1]

L. M. Schetky, Scientifi American 241, 82 (1979)

View on Pith 1979
[2]

W. J. Buehler, J. V. Gilfrich and K. C. Weiley, J. Appl. Physics 34, 1467 (1963)

View on Pith 1963
[3]

H. C. Donkersloot and J. H. N. VanVucht, J. Less Common Met. 20, 83 (1970)

View on Pith 1970
[4]

B. K. Das, M. A. Schmerling and D. D. S. Lieberman, Mat. Sci. Eng. 6, 248 (1970)

View on Pith 1970
[5]

R. W. Fonda, H. N. Jones and R. A. Vandermeer, Scripta Mat. 39, 1031 (1998)

View on Pith 1998
[6]

M. A. Schmerling, B. K. Ds and D. S. Lieberman, Met. Trans. 1, 3273 (1970)

View on Pith 1970
[7]

Z. Nishayama, Martensitic Transformations (Academic Press, NY, 1978)

View on Pith 1978
[8]

Martensite, G. B. Olson and W. S. Owen, eds., (ASM International , Materials Park, Ohio, 1992)

View on Pith 1992
[9]

S. M. Shapiro in Magnetism and Structure in Functional Materials (Springer, Heidleburg, 2005)

View on Pith 2005
[10]

B. Das. And D. S. Lieberman, Acta Met. 23, 579 (1975)

View on Pith 1975
[11]

B. Das, E. A. Stern and D. S. Lieberman, Acata Met. 24, 37 (1976)

View on Pith 1976
[12]

B. H. Chen and H. F. Franzen, J. of Less-Common Met. 153, L13 (1989) 13 G. D. Gu, M. Hucker, Y. J. Kim, A. Li and A. R. Moodenbaugh, J. Crystal Growth 287,318 (2006)

View on Pith 1989
[14]

Neutron News 3, 29 (1992)

View on Pith 1992
[15]

R. W. Fonda, H. N. Jones and R. A. Vandermeer, Scripta Met. 39, 1359 (1998)

View on Pith 1998
[16]

T. Davenport, L. Zhou and J. Trivisonno, Phys. Rev. B 59,3421 (1999)

View on Pith 1999
[17]

J. Worgull, E. Petti, and J. Trivisonno, Phys. Rev. B 54, 15695 (1996)

View on Pith 1996
[18]

O. Mercier, K. N. Melton, G. Gremaud, and J. Hagi, J. Appl. Phys. 51, 1833 (1980)

View on Pith 1980
[19]

S. Zirinsky, Acta Metall. 4, 164 (1956)

View on Pith 1956
[20]

S. M. Shapiro, B. X. Yang, Y. Noda, L. E. Tanner and D. Schryvers, Phys. Rev. B 44, 9301 (1991). 21, A. Zheludev, S. M. Shapiro, P. Wochner and L. E. Tanner, Phys. Rev B 54, 15045 (1996)

View on Pith 1991
[22]

C. Zener, Phys. Rev. 71, 846 (1947)

View on Pith 1947
[23]

H. Tietze, M. Müller, and B. Renker, J. Phys. C: Solids State Phys. 17, L529 (1984)

View on Pith 1984
[24]

T. Ohba, S. M. Shapiro, S. Aoki and K. Otsuka, Jpn. J. Appl. Phys. 33, L1631 (1994)

View on Pith 1994
[25]

H. G. Smith, Phys. Rev. Lett. 58, 1228 (1987)

View on Pith 1987
[26]

M. Sato, B. H. Grier, S. M. Shapiro, and H. Miyajima, J. Phys. F: Met. Phys. 12, 2117 (1982)

View on Pith 1982
[27]

G. L Zhao and B. N. Harmon, Phys. Rev. B 45, 2818 (1992)

View on Pith 1992
[28]

A. D. Bruce and R. A. Cowley, Structural Phase Transitions (Taylor & Francis, London (1981). 12 Figure Captions: Figure 1: Intensity contours of elastic scattering for spectrometer set for the β -phase (1,1,0) (left side) and (2,0,0) (right side). Top row is measured at 900°C in the β-phase. Second row is 875°C in the β’-phase. Third row is measured at 60...

View on Pith 1981

Discussion

Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.

[1] [110]

60.9 11.6 TABLE III Elastic Constants (Measured at 1100°C) Elastic Constant 1011 dynes/cm2 C11 20.7 C44 3.9 C’=1/2(C11-C12) 0.81 C12 19.1 14 Figure 1 15 Figure 2. 16 Figure 3 17 Figure 4 18 0 1 2 3 4 5 0 0.05 0.1 0.15 0.2 NbRu [qq0]-TA2910°C 950°C 1000°C 1100°C 1250°C 1550°C Energy (meV) [qq0] Figure 5 19 Figure 6. 20 0 200 400 600 800 1000 0 0.050.10.150...

View on Pith

[2] [1]

L. M. Schetky, Scientifi American 241, 82 (1979)

View on Pith 1979

[3] [2]

W. J. Buehler, J. V. Gilfrich and K. C. Weiley, J. Appl. Physics 34, 1467 (1963)

View on Pith 1963

[4] [3]

H. C. Donkersloot and J. H. N. VanVucht, J. Less Common Met. 20, 83 (1970)

View on Pith 1970

[5] [4]

B. K. Das, M. A. Schmerling and D. D. S. Lieberman, Mat. Sci. Eng. 6, 248 (1970)

View on Pith 1970

[6] [5]

R. W. Fonda, H. N. Jones and R. A. Vandermeer, Scripta Mat. 39, 1031 (1998)

View on Pith 1998

[7] [6]

M. A. Schmerling, B. K. Ds and D. S. Lieberman, Met. Trans. 1, 3273 (1970)

View on Pith 1970

[8] [7]

Z. Nishayama, Martensitic Transformations (Academic Press, NY, 1978)

View on Pith 1978

[9] [8]

Martensite, G. B. Olson and W. S. Owen, eds., (ASM International , Materials Park, Ohio, 1992)

View on Pith 1992

[10] [9]

S. M. Shapiro in Magnetism and Structure in Functional Materials (Springer, Heidleburg, 2005)

View on Pith 2005

[11] [10]

B. Das. And D. S. Lieberman, Acta Met. 23, 579 (1975)

View on Pith 1975

[12] [11]

B. Das, E. A. Stern and D. S. Lieberman, Acata Met. 24, 37 (1976)

View on Pith 1976

[13] [12]

B. H. Chen and H. F. Franzen, J. of Less-Common Met. 153, L13 (1989) 13 G. D. Gu, M. Hucker, Y. J. Kim, A. Li and A. R. Moodenbaugh, J. Crystal Growth 287,318 (2006)

View on Pith 1989

[14] [14]

Neutron News 3, 29 (1992)

View on Pith 1992

[15] [15]

R. W. Fonda, H. N. Jones and R. A. Vandermeer, Scripta Met. 39, 1359 (1998)

View on Pith 1998

[16] [16]

T. Davenport, L. Zhou and J. Trivisonno, Phys. Rev. B 59,3421 (1999)

View on Pith 1999

[17] [17]

J. Worgull, E. Petti, and J. Trivisonno, Phys. Rev. B 54, 15695 (1996)

View on Pith 1996

[18] [18]

O. Mercier, K. N. Melton, G. Gremaud, and J. Hagi, J. Appl. Phys. 51, 1833 (1980)

View on Pith 1980

[19] [19]

S. Zirinsky, Acta Metall. 4, 164 (1956)

View on Pith 1956

[20] [20]

S. M. Shapiro, B. X. Yang, Y. Noda, L. E. Tanner and D. Schryvers, Phys. Rev. B 44, 9301 (1991). 21, A. Zheludev, S. M. Shapiro, P. Wochner and L. E. Tanner, Phys. Rev B 54, 15045 (1996)

View on Pith 1991

[21] [22]

C. Zener, Phys. Rev. 71, 846 (1947)

View on Pith 1947

[22] [23]

H. Tietze, M. Müller, and B. Renker, J. Phys. C: Solids State Phys. 17, L529 (1984)

View on Pith 1984

[23] [24]

T. Ohba, S. M. Shapiro, S. Aoki and K. Otsuka, Jpn. J. Appl. Phys. 33, L1631 (1994)

View on Pith 1994

[24] [25]

H. G. Smith, Phys. Rev. Lett. 58, 1228 (1987)

View on Pith 1987

[25] [26]

M. Sato, B. H. Grier, S. M. Shapiro, and H. Miyajima, J. Phys. F: Met. Phys. 12, 2117 (1982)

View on Pith 1982

[26] [27]

G. L Zhao and B. N. Harmon, Phys. Rev. B 45, 2818 (1992)

View on Pith 1992

[27] [28]

A. D. Bruce and R. A. Cowley, Structural Phase Transitions (Taylor & Francis, London (1981). 12 Figure Captions: Figure 1: Intensity contours of elastic scattering for spectrometer set for the β -phase (1,1,0) (left side) and (2,0,0) (right side). Top row is measured at 900°C in the β-phase. Second row is 875°C in the β’-phase. Third row is measured at 60...

View on Pith 1981