I have an austenitic steel which contains both M7C3 and M23C6 (mainly Cr7C3 and Cr23C6) carbides. Can anyone give me a tip on how to detect these phases with the help of EBSD (together with EDS)? How much eV should I use? Tips for software AZtec?
With these carbides you should have no problems until single particles are getting smaller than ~ 500 nm. I would use 20 kV. Aztec should easily distinguish cubic M23C6 from austenitic matrix.
Remember the most important is sample preparation.
In attachment you can see M23C6 pattern can look very similar to FCC austenite but M7C3 is much different.
I think , you can use EBSD in phase analysis mode and also consider your step size less than 1 um. During or meanwhile post-processimg, you should try to find better crystallographic structre for the carbides in your software.
Besides, you can do phase map analysis before EBSD with the same step size and magnification an location.
If you think your carbides are on surface and they are very fine , you shoud start with lower accelerated volatge 5 to 20 Kv or even start from 1 Kv.