Chemical etching of dislocations and grain boundaries in ordered Ni{sub 3}Al crystals
- Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Solid State Physics
- Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics
A new selective chemical etchant is developed and tested for its ability to reveal dislocations in Ni{sub 3}Al single crystals. The best results have been found for the mixed solution of HNO{sub 3}/HCl/H{sub 2}O (1:1:1 volume ratio) with the aqueous solution of FeCl{sub 3} {center_dot} 6H{sub 2}O (over a range of 0.01--0.002 M). The etchant forms etch pits with the properties typical of dislocation etch pits. The etchant reveals both individual dislocations and dislocations in grain boundaries before and after different types of deformation of Ni{sub 3}Al samples. The features of the etchant, such as retaining the desired high contrast, the increase of the etch pit size with etching time, repeatability and practical convenience, make the developed etchant a good candidate for various applications, such as revealing dislocation structures on {l_brace}001{r_brace} and close surfaces and measuring dislocation mobility in Ni{sub 3}Al crystals. When combined with chemical polishing, the etchant is of prime interest, among other things, for studying the dislocation structure and its modification in the bulk of plastically deformed samples. The etching patterns demonstrate that the macroscopic motion of dislocations in Ni{sub 3}Al under local or bending deformation takes place mainly in the <{bar 1}10>{l_brace}111{r_brace} primary glide systems. Some indication of dislocation cross slip and multiplication was also observed in the studied samples.
- OSTI ID:
- 205222
- Journal Information:
- Scripta Materialia, Vol. 34, Issue 7; Other Information: PBD: 1 Apr 1996
- Country of Publication:
- United States
- Language:
- English
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