Aluminum crankcase, aluminum timing ring, even if they are different grades, I'd bet that the coefficient of thermal expansion is going to be very close. Vibration, well this is a very small part located around the C/L of the crank, any acceleration/deaccelerations are going to be very small. This little part only weighs a few grams so it's not going to take too much to hold it in place. If you were hanging a 4lb shop hammer off the rear in this fashion, then I'd share your concerns. Anyhow, mine is now attached permanently and I'm not the least bit worried about it coming off. Guess you could use one of the high temp RTVs if you are worried about the heat and vibration.