Dear Sir/Madam,
I am working in nano indentation. According to Hall-petch relation when substrate temperature increases it leads to increase in crystallite size and decrease in hardness of the film. But in my case when substrate temperature increases, both crystallite size and hardness also increases. May I know what happens in that?
Hi,
I’ve actually encountered a similar behavior of coatings in the past.
The thing is that if you have a micro-structured coating then the film hardness may initially increases (along with the substrate’s temperature up to 200oC) due to dislocation movement within its micro-structure, after this point the hardness will however drop rapidly and may again show a slight increase at around 400oC (this time due to diffusion phenomena).
Hope it helped!
Alex
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