I can't tell if you are honestly ignorant, trolling, or attempting to be deceptive...
That CVR didn't HIT the ground at 700kph... not even close.
Lets take our example - 700 kph, 45 meter overall length (assume 40 meters to account for the CVR being mounted somewhere in the tail).
If we assume the impacted surface (rock) to be completely and utterly immobile (it isn't, but it makes for a far simpler calculation and would actually result in a far greater force estimate)
The force being exerted upon the aircraft (work required to stop it) comes to approximately 4,400 tons, or 39,000,000 newtons at the time of impact. Now, factor this being spread across the collapse of 40 meters of fuselage, plus the wings and other components impacting, etc... the overall force exerted upon the CVR becomes much, much less.
Granted, it still most likely hit the dirt at a significant velocity - but it was nowhere near 700kph. If it were, even it would acted more like a liquid upon impact than a piece of metal.