We have seen a slight increase in the stacking fault energy with strain rate for aluminum alloys (6061, 2024, and 8090).  The effect is more pronounced when you have second phases like SiC and Al2O3 (in composite form) because of the alignment issues with the stacking faults in the reinforcing particles and shuffle planes in the alloys.  There are a number of papers published in the field.

In a single phase alloy the stacking fault energy is an intrinsic property of the crystal structure alone; therefore stacking fault energy should not vary with external factor, like strain rate. But, temperature can have effect as it induces changes in interatomic distances and dialates the lattice. As Rajendra U. Vaidya suggested, presence of a second phase can have pronounced effect, especially if it is coherent with the primary phase.

Sir

Thanks a lot for the reply. 

Can you help me with these queries.

How does the stacking fault probability depend on strain rate.  

I mean stacking fault density in a material increase or decreases as a function of temperature, strain rate and alloying addition (especially interstitial atoms).

Is there any method to calculate the SFE density/fraction in a material. ??

Thanking you

Santosh