1990 Fiscal Year Final Research Report Summary
Elasticity and Unelasticity of Intermetallic Compounds
Project/Area Number 
01460213

Research Category 
GrantinAid for General Scientific Research (B)

Allocation Type  Singleyear Grants 
Research Field 
Physical properties of metals

Research Institution  Kyoto University 
Principal Investigator 
KOIWA Masahiro Kyoto University Department of Metal Science and Technology, Professor > 京都大学, 工学部, 教授 (00005860)

CoInvestigator(Kenkyūbuntansha) 
NUMAKURA Hiroshi Kyoto University Department of Metal Science and Technology, Instructor, 工学部, 助手 (40189353)

Project Period (FY) 
1989 – 1990

Keywords  Elastic constants / Rectangular parallelepiped resonance method / Intermetallic compounds / Nonstoichiometry / Nibase compounds / Anisotropy factor 
Research Abstract 
1. The Rectangular Parallelepiped Resonance (RPR) method has been known to be a powerful method for determining the elastic constants, but the amount of numerical calculations for the data analysis is quite large. A new method of analysis is proposed, which is applicable to the case of specimens of cubic crystals. In this method, the resonance frequencies are calculated and stored for various combinations of Poisson's ratio, nu and anisotropy factor. A. The measured spectrum of resonance frequencies is compared in turn with the calculated spectra by a procedure of something like pattern comparison so as to determine roughly the values of elastic constants. Final refinements can be done successfully by the interpolation of the stored data. 2. The three elastic stiffness constants of various Nibased intermetallic compounds Ni_3X (X=Mn, Fe, Al, Ga, Ge and Si) with L1_2 structure have been determined at room temperature by the rectangular parallelepiped resonance method. The elastic anisotropy factor, A, of the compounds is ge nerally large, ranging from 2.5 to 3.3, except for Ni_3Ge(A=1.71). The elastic constants exhibit some correlation with the lattice constants. The minor element, X, can be regarded as exerting "chemical pressure" which causes the expansion of the Ni lattice, thus resulting in the decreaseof the elastic constants. 3. The selfdiffusion coefficients of both the constituents (D _<Ni> and D_<Ge> in Ni_3Ge) have been first measured for L1_2 compounds. The relation of the selfdiffusivities in the temperature range from 1173 to 1273 K is given as follows : 22< D _<Ni>/D_<Ge><29, where D is selfdiffusion coefficient.

Research Products
(9 results)