THE STUDY OF PHASE COMPOSITION OF HIGHLY COERCISE ALLOYS WITH Fe-Ni-Al-CO-Ti AS THE BASE BY MEANS OF γ-RESONANCE SPECTROSCOPY

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THE STUDY OF PHASE COMPOSITION OF HIGHLY COERCISE ALLOYS WITH Fe-Ni-Al-CO-Ti

AS THE BASE BY MEANS OF γ -RESONANCE SPECTROSCOPY

A. Izgorodin, M. Shipko

To cite this version:

A. Izgorodin, M. Shipko. THE STUDY OF PHASE COMPOSITION OF HIGHLY COERCISE AL- LOYS WITH Fe-Ni-Al-CO-Ti AS THE BASE BY MEANS OF

γ-RESONANCE SPECTROSCOPY.

Journal de Physique Colloques, 1980, 41 (C1), pp.C1-369-C1-370. �10.1051/jphyscol:19801139�. �jpa-

00219623�

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JOURNAL DE PHYSIQUE Colloque C l

,

supplt!ment au n ^O^1,Tome ^41,janvier ^1980,page ^C1-369

M E STUDY OF PHASE COMPOSITION OF HIGHLY COERCISE ALLOYS W I M Fe-Ni-A1-CO-Ti AS M E BASE BY MEANS OF Y-RESONANCE SPECTROSCOPY

A.K. Izgorodin and M.N. Shipko

Physics Department Textile I n s t i t u t e , 153475 Ivarwvo

,

²¹^D. Engels S t . , USSR.

It has been found that highly coercive alloys of KIHDKT type possess coercive force of 2000 Oe and have magnetic energy amounting to 12nlnGsOe,that makiag it possible to employ them in various

magnetic systems. However, there are some A,

factors which hold back the broad usage

of the said alloys. Specifically, at room 572-

temperature the alloys remain in extreme-

ly fragile condition

[I] .

The problem of

-

- 5 -3 -1 +1 + 3 +5 +7

increasing magnets' resistance to propa

-

_Vet

_osity

_fmm/sec)

gation of splits, the development of

techno lo,^

enablipg to obtain regularly Pie.1. Zlossberuer spectra of

HHDK

35T5 desired operating qualities, as vtell as alloy: a-alloy hardening at 124G°C;

theoretical determination of greatest b-working condition.

possible magnetic characteristics can not be resolved without detailed knowledge about phase composition a:ld phase transformations developing in alloys. The pre- sent paper considers the usage of Xos

-

sbauer micro-roentgen-spectrtun analysis and differential thermal analysis (DTA) in studying the phase composition ofH)HDK

35T5

alloy subjected to different kinds of heat treatment. Uossbauer spectra were produced on

ffrPC-4

spectrometer, the source of

I f

radiation being

: C

isotope in

C r

matrix.

The spectrum of the eample hardened at 1240°C has manifested itself in a six- line picture of superfine structure (SFS) with noticably broadened components (Fig.

la), these testifying to the majority of iron atoms being distributed in accor

-

dance with the rules of statistics. At the same time it may be concluded that slight effect of ordering is being deve- loped because some of the lines have proved to be splitted (Fig. la). DTA curve (Fig. 2a) shovrs that with the rise of temperature the anthelpy of hardened alloy also changes. Up to 600°C the

change proceeds approximately in straight line, thus pointing to the absence of ordering a d disordering procesees whatever.

Hardened alloy's 12 min ageing at 800°C results in emergence of phases

Pz

^and

regulated in a manner consistent withNIJAi and

Ni A\

resp.ectively. The processes of tempering aiming at converting the alloy into working condition are accompanied by increased effect of phases' ordering. L3- cal fields in

Fe

atomst nuclei arranged in the corners of phase

Pz

cubes have gone up from 320kOe to 346kOe, the fields of phase

-

from 335kOe to 3651rOe (Pig.

~b). Nametic moment of

F e

nuclei locat- ed in the ceritre of phasept unit cell becomes insignificantly less (from 281kGe to

275kOe).

Apperantly the described transformations in magnetic moments of

Fe

nuclei emerge not only from the redistsi- bution of components between phasesp,and

p ,

as it was thought earlier

[z] ,

^but

also as a result of regulating processes taking place in each phase, there being some grounds to suppose that the processes of regulating when tempering play the leadfng part in c h w i n g magnetic moments

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19801139

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C1-370 JOURNAL DE PHYSIQUE

of

Fe

n u c l e i , Besides, p a r a l l e l w i t h t h e r e d i s t r i b u t i o n of atoms some zones a r e formed where t h e atoms remain i n paramag- n e t i c s t a t e . I n t h e c e n t r a l s e c t i o n of t h e sample's spectrum (Pig. I b ) t h e r e i s a s l i g h t l y broadened l i n e t h a t vras found

a l l o y i n q u e s t i o n w a s v e r y much l i k e t h a t of a n a l l o y produced by c a s t i n g and b e i n g hardened a t 1240°C, The p r o c e s s e s of age-

i n g 776th subsequent tempering a r e accompanied by phase o r d e r i n g and emergence of

F e n u c l e i b e i n g i n p a r m a g n e t i c s t a t e , The i n t e n s i v i t y of SFS s p e c t r a c o n s t i t u - e n t s t y p i c a l of

Fe

n x c l e i and disposed i n t h e c e c t r e of u n i t c e l l ' s cubes n o t i c a b l y i n c r e a s e s ,

1. I z g o r o d i n A.R. R e g u l a r i t i e s of F a i l u r e of Highly Coercive Alloys with

Fe - N i - A t

a s t h e Base and Xethods f o r E s t i m a t i o n of T h e i r B r i t t l e n e s s .

-

Book: P h y s i c a l and Chemical Mechanics o f Friction Processes.

Ivanovo,

1978,

pp. 69-74.

2, P o v i t s k i y V.A. and o t h e r s . Mossbauer Study of Thermomagnetic Treatment of T i - konal Alloy.

-

P h y s i c s and C e t a l S t u & ~ , 1970, ed.2, v.29, pp, 247-251.

P i g . 2. Curves of d i f f e r e r t i a l thermal a n a l y s i s of

KIHDK

35T5 a l l o y : a

-

h a r d e n i n g a t 1240°C;

b

-

working c o n d i t i o n .

e a r l i e r 5y o t h e r a u t h o r s [2]

.

Metallogra- phy and c a n e r a p i c t u r e s of ground s a u p l e s subjected t o 3500hrs a g e i n g a t 770°C hzve proved t h e a v a i l a b i l i t y of t h r e e c o a g u l a t - ed phttses. I n a d d i t i o n t o phases

53

^and

t h e r e have been observed c e r t a i n zones r i c h i n l i g h t c o n s t i t u e n t s . The DTA dia- Frzm (Pig, 2b) shows t h a t i n c a s e of a l -

..>

l o y s b e i n g t r e a t e d t o ~ a r d s working coniri- t i o n t h e t h r e e phases bccome d i s o r d e r e d , t h e Ccvelopnent t a k i n g p l a c e i n zones of 320, 460 and 575'C.

The SFS s p e c t r a mere a l s o o b t a i n e d

011 samples which upon t r e a t i n g toviards working conditiol? underneilt tempering at 770°C f o r 3500hrs. Though t h e phases be- i n g p r o c e s s e d i n t h a t way a r e fount t o be

i n

c o a g u l a t e d s t a t e a l l o y ' s s p e c t r a have llot undergone c o n s i d e r a b l e changes.Having been hardened a t 1240°C tile spectrum of