As memory serves, it was the main rotor hub spindle sleeve on the 76 that was the problem. In at least two fatal instances the sleeves moved outward allowing the spindles to overflex and eventually fail. Sikorsky added a plastic cuff that prevents the sleeve from sliding out and, more importantly, added a stainless steel bolt through the spindle that is capable of bearing the entire centrifical load should the spindle break.
The blades themselves are pretty robust to say the least. I'm aware of one instance of poor auto rotation technique, where the main rotor rpm got down to less than 50%. One blade actually bent - one blade had its damper attachment point ripped out - the pilot was lucky that day.
Speaking of titanium; I'm always amazed at it properties. 76 blade spares, hubs on ST's & 412's, things that flex hundreds of millions of times over their life. On the other hand it is known to have a brittleness. Years ago, the 412 had a problem with a cracked hub and it was found to have been a static stress from a blade flexing up during a thunderstorm. Grumman tried titanium hydraulic lines in the F14 until one broke causing a crash. The Air Force used special brass tools on their SR71's to avoid scratching the metal which can cause stress. So, the question is: what other components use titanium bolts or studs?