Dear Sir,
Thank you very much for your reply.
I minutely checked the things and following is the
accurate data I have
No Load Ni Ti Sample:
calculated d spacing from ring is
3.07,
2.417(this is a faint line in ring pattern I couldn't
index this. )
2.1040,
1.4883,
1.21017
out of these five lines I have indexed four accuraely
as in front std 'd' spacing given
(1 0 0) 3.00926
(1 1 0) 2.12787
(2 0 0) 1.50463
(211) 1.22853
2.417 d spacing ring disappears as I stress the SMA
sample (Aus to Martensite transformation) and when I
agian unload the sample it reappears at 2% strain
continues to appear upto full unloading (0% strain)
when you again load the sample you will see the same
ring upto 3% strain.After that it disappears.
I have seen the pearsons data to locate that ring
Ni4Ti3 phase Pd4Pu3 hR14 hexagonal
9.734125539 1 0 0
5.62 1 1 0
4.867062769 2 0 0
4.867062769 2 0 0
4.501508735 1 0 1
3.679153629 2 1 0
3.513407213 2 0 1
2.979147198 2 1 1
2.5385 0 0 2
2.456348032 1 0 2
2.313447019 1 1 2
NiTi phase NiTi str mp4
0 1 1 3.070299698
1 0 0 2.85522823
-1 1 0 2.344914921
1 1 0 2.344914921
0 0 2 2.309230182
Above both std are having Hexagonal and monoclinic
str.
In Austenite of Ni-Ti B2 Str is there,In B2 str std D
spacing is
(1 0 0) 3.00926
(1 1 0) 2.12787
(1 1 1) 1.7374
(2 0 0) 1.50463
(2 1 0) 1.34578 means its not contaning 2.41 d spacing
reflection....
About My previous questions, I found the answeres now.
Only this 2.41 d spacing faint line I am following
now.
Any help regarding this will be appreciated.
Thank you once again.
Regadrs
Chandra
--- Robin Shirley <[EMAIL PROTECTED]> wrote:
> Dear Chandra
>
> Firstly, you don't have enough lines in either of
> your two observed (?)
> patterns to index them ab initio from internal
> evidence alone.
>
> Five or six lines are not enough, even to index a
> supposedly cubic
> pattern without additional information either from
> other measurements or
> from the literature.
>
> Also, the status of your data is unclear:
>
> a) How accurate are they?
> b) What is the wavelength and how well do you know
> it?
> c) Are they observed data, or calculated, or a
> mixture of the two?
>
> Referring to your paragraph numbers:
>
> A The 5-line NiTi SMA ring-diffraction pattern
>
> Your second line "d=2.544763147" appears not to be
> an observed line but
> presumably a calculated one, since the ratio of its
> d with that of the
> first line is exactly 0.8 to 8 significant figures.
>
> The remaining 3 lines have values of cubic N (=Q/Q1)
> of 2.08, 3.02 and
> 4.05, so they could be 110, 111 and 200 if the
> precision of your
> measurements was only about 3%.
>
> In order for your line 2 to fit a cubic sequence,
> the values of N would
> need to be 16, 25, 32, 48 and 64 (i.e. 400, 500,
> 440, 444 and 800).
>
> But, as I've said, line 2 doesn't seem to be an
> observed line anyway.
>
> For your four lines (omitting line 2) to match the
> calculated
> austenite-b2 NiTi pattern that you quote, either
> your wavelength would
> need to be some 5% larger than you think it is, or
> considerable lattice
> expansion would need to be present (from thermal
> expansion or some other
> cause), or some combination of these.
>
> B The stressed NiTi pattern
>
> This appears to be unrelated to the monoclinic
> martensite-b19' NiTi
> pattern that you quote, and contains far too few
> lines to index ab
> initio, so your only hope is to find some
> appropriate reference
> pattern(s).
>
> I suspect that you will need a better knowledge of
> the wavelength(s) used
> and of the purity and nature of your sample(s) to
> get further with these
> investigations.
>
> Perhaps someone in the list can point you towards
> reference patterns
> that may help.
>
> With best wishes
>
> Robin Shirley
>
> ---------------------------------
>
> Date: Thu, 19 Jul 2001 11:08:20 -0700 (PDT)
> From: CHANDRASEN RATHOR
> <[EMAIL PROTECTED]>
> Subject: NiTi SMA diffraction pattern indexing
> To: [EMAIL PROTECTED]
> Reply-to: [EMAIL PROTECTED]
>
> Hi,
>
> I am having problem with indexing of ring
> diffraction
> pattern obtained by Synchrotron radiation NiTi SMA
> alloy in no stress and stressed condition.
>
> 1.I have calculated 'd' spacing for each ring.
>
> A. For no load condition (austenite-b2 structure)
> calculated 'd(in angstrom)' data is
>
> 3.180953934,2.544763147,2.20295878,1.830587683
> 1.580730311
>
> by STD. hkl reflection d spacing for austenite Ni-Ti
> is
> (1 0 0) 3.00926
> (1 1 0) 2.12787
> (1 1 1) 1.7374
> (2 0 0) 1.50463
> (2 1 0) 1.34578
>
> I can understand ordered b2 structure of austenite
> acts as simple cubic in diffraction behavior.I can
> index the data easily, but 2.544763147 this
> calculated
> 'd' i couldn't fit with STD data.
>
> Also in stressed condition i am getting first
> reflection 'd'spacing claculated is 4.266783322 and
> by
> STD what i have is (0 1 1) 3.07927.which is not at
> all
> matching.
>
> B.For stressed condition (martenisite- b19'
> monoclinic)of NiTi sample calculated 'd(in
> angstrom)'from diffarction ring data is
>
>
4.266783322,3.224330579,2.556226044,2.25191342,1.818853147,1.585145759
>
> by STD. hkl reflection d spacing for martensite
> Ni-Ti
> is
>
> (0 1 1) 3.07927,(1 0 0) 2.86543,(-1 1 0)2.52841,(1 0
> 1)2.35966,(1 1 0) 2.34098,(0 2 0) 2.29035,(-1 1
> 1)2.16035
> (0 0 2) 2.07962,(1 1 1) 2.04004,(1 2 1) 2.00628,(0 1
> 2)1.89361,(-1 2 0)1.86867,(1 0 2) 1.68307,(1 2 0)
> 1.71884
> (-1 2 1)1.70454,(-1 1 2)1.60613,(1 2 1) 1.58854
>
>
> WHEN I SEARCHED FOR CRYSTALLOGRAPIC DATA FOR NI-TI
> intermettalic PHASE, I CAME TO KNOW VARIOUS
> INTERMEDIATE PHASES AS Ni3Ti(hexagonal DO24 str) ,
> NiTi (cubic) ,
> piTi-Ni (hexagonal?) ,NiTi2(cubic)
>
> have anyone gone through indexing diffraction
> pattern
> for SMA NiTi alloy ?where I will find standard d
> spacing for various h,k,l reflection in in above all
> phase structures.?
>
> Any help would be greatly appreciated.
>
> Chandra
> University of central florida.
>
__________________________________________________
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/
