Lattice imperfections studied by X-ray diffraction in deformed aluminum-base alloys: Al-Cu alloy
- PDF / 421,920 Bytes
- 3 Pages / 630 x 792 pts Page_size
- 0 Downloads / 228 Views
,00.c
Liquid
16oo
Lattice Imperfections Studied by X-Ray Diffraction in Deformed Aluminum-Base Alloys: AI-Cu Alloy
4oo o
o
S.K. CHATTOPADHYAY, S.K. CHATTERJEE, and S.P. SENGUPTA The present analysis is a continuation of the program of study of lattice imperfections in deformed aluminumbase alloys. ~ Detailed X-ray diffraction study t2-6] has been performed on aluminum-base copper alloys in four different compositions, namely, 0.32, 0.84, 1.15, and 1.26 at. pct of Copper. The alloys were prepared from spectroscopically pure ingredients supplied by JohnsonMatthey Co. Ltd., London, by following the procedure adopted in the preceding work of this series. [~] The alloys were later homogenized at 530 ~ for 15 days in the face centered cubic phase (Figure 1). The cold working was achieved as usual by hand filling. A portion of the filling from each alloy was annealed at 520 ~ to relieve the stress so that the same be used as standard for the Stokes' instrumental correction done earlier. The same procedure tl] was followed to prepare a sample for the Siemens Kristallofluex-4 X-ray diffractometer, and X-ray diffraction profiles were recorded by using CuK~ radiation. The detailed line shift, line asymmetry, and line shape analyses were performed by following the procedures and using the equation mentioned used before. [1'4-s] The microstructural parameters, like coherent domain sizes (De), microstrain (e~), stacking faults or', cz" (intrinsic and extrinsic), deformation twin fault/3, dislocation density p, and stacking fault energy parameter 7//x, were determined. The line shift analysis was done by using the neighboring peaks and considering the effects of lattice parameter change Aa/ao and intrinsic and extrinsic faulting (a' - a"). The residual stress or in these alloy systems was considered to be zero as it is considered for random powder sample, t~'4-61 The values of lattice parameter change Aa/ao which is due to dislocation arrangements were found to be extremely small, indicating negligible distortion of the lattice on cold work. The values of (a' - a"), neglecting Aa/ao, were also calculated and are shown in the Table I. The small values o f (a' - a"), almost within the error limits, show a negligible effect of faulting. Unlike t h e AI-Ge system, t~] where a slight indication of the faulting was observed at the higher concentration of Ge, this alloy system shows a negligible effect of faulting even at higher concentration. This is also evident from the negligible fluctuation of the lattice
S.K. CHATTOPADHYAY, Lecturer, Department of Metallurgical Engineering, and S.K. CHATTERJEE, Assistant Professor, Department of Physics, are with the Regional Engineering College, Durgapur, India. S.P. SENGUPTA, Professor and Head, is with the Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Calcutta, India. Manuscript submitted January 22, 1991. METALLURGICAL TRANSACTIONS A
300 200 f0o I
60
~ S0
70
1000
l 90
Wt *]o At Fig. 1 - - T h e phase diagram of the AI-Cu system.
LI
Data Loading...
