On the austenite ordering and martensite tetragonality in off-stoichiometric Fe 3 Pt alloys
- PDF / 342,111 Bytes
- 3 Pages / 612 x 792 pts (letter) Page_size
- 32 Downloads / 196 Views
Alloy
Temperature, ~
Hardness,HKsoo
Ti-1.4 Ni Ti-2.2 Mo-1.5 Ni Ti-1.4 Ni Ti-2.2 Mo-l.5 Ni
700 700 1100 1100
178 247 210 313
s m a l l a m o u n t of m o l y b d e n u m . E s s e n t i a l l y , t h e e f f e c t s of a d d i n g M o t o t h e T i - 1 . 4 N i a l l o y f o r t h e h e a t t r e a t ments applied in this study are the following: 1) F o r t h e 700~ h e a t t r e a t m e n t , a d d i n g M o r e s u l t s in a finer grained microstructure with alternating g r a i n s of o t - T i a n d / 3 - T i . T h e / 3 - T i a r e a c o n t a i n s a widely dispersed, small sized precipitate phase. 2) T h e a d d e d M o p r o d u c e s a g r a i n s t r u c t u r e w h i c h i s m o r e e l o n g a t e d a n d l e s s e q u i a x e d t h a n t h a t of T i 1 . 4 N i a t 700~ 3) T h e M o a d d i t i o n t o t h e T i - l . 5 N i a l l o y e n h a n c e s the martensitic reaction and forms a hard acicular martensite which is not present in the binary Ti-1.4Ni alloy after heat treating at ll00~ T h e a u t h o r g r a t e f u l l y a c k n o w l e d g e s M r . F r a n k S. Biancaniello for heat treating the specimens, Mr. Cletus J. Bechtoldt for the X-ray diffraction work and M e s s r s . C h a r l e s H. B r a d y a n d D o n a l d L . M a s k e f o r the photographic work.
On the Austenite Ordering and Martensite Tetragonality in Off-Stoichiometric Fe3Pt Alloys H . C H A N G , S. HAHN, A N D S. S A S T R I It i s w e l l e s t a b l i s h e d t h a t t h e a u s t e n i t e t o m a r t e n s i t e t r a n s f o r m a t i o n i n t h e a l l o y s of n e a r F e 3 P t c o m p o s i t i o n i s g r e a t l y a f f e c t e d b y t h e d e g r e e of a t o m i c order in the anstenite state, Dunne and Wayman 1 and Kajiwara and Owen 2 have shown by their resistivity m e a s u r e m e n t s o n a 24 a t , p e t P t a n d a 25 a t . p e t P t alloy, respectively, that the M s temperature and the thermal hysteresis between M s and A s decreased m a r k e d l y a s t h e d e g r e e of o r d e r i n t h e i r a l l o y s w a s i n c r e a s e d . T h e t r a n s f o r m a t i o n of a u s t e n i t e t o m a r tensite is accompanied by the crystal structure change of f c c t o b c c i n t h e d i s o r d e r e d a l l o y s . It w a s g e n e r a l l y assumed that the same structure change was valid for partially ordered or fully ordered alloys. For example, Kajiwara and Owen apparently assumed the cubic structure for the martensite transformed from the partially ordered austenite. 2 However, a closer e x a m i n a t i o n of o n e of t h e i r e l e c t r o n d i f f r a c t i o n p a t H. CHANG, S. HAHN, and S. SASTRI are R & D Scientist, Metallurgist, and Director, respectively, Chemical and Materials Research Division, Boston Research and Development Laboratory, Gillette Co., Boston, MA 02106. Manuscript submitted February 4, 1976. 1796 VOLUME 7A, NOVEMBER 1976
1. N. G. Feige and T. J. Murphy: Corrosion Resistance of Titanium and Ti-2Ni in Hot Brine Environments, presented at the NACEMeeting,Houston, Tex
Data Loading...
