Hey Hitpawz -
You will have to set this up using Matinee and a Level Blueprint. Create an Event Track in Matinee and Choose at what point in your timeline you want the change to happen then call a reference of the matinee actor in your level blueprint. You will then pull off of the event output pin from the Referenced Matinee actor and change your MIC information in the Blueprint Event Graph. I would also recommend the use of a Material Parameter Collection which will eliminate the need to make direct material changes and just smoothly transition variables.
Thank You
Eric Ketchum