Sunday, 40 km in and after a steep uphill, the pivot point on my front derailleur snapped in two parts. 

I remember a whipe noise, one of the chain link opened and when I tried to place the chain back in after removing the faulty link I notice the silvery part of the derailleur was rubbing on the big gear and found about the material failure.

My question is : is that a common issue ? What did I do wrong (maintenance ? Usage?) and how can I prevent the issue in the future. 

The bike had 6000 km in about a year of use and was serviced by the manufacturer one month before that.[![material failure][1]][1]



  [1]: https://i.sstatic.net/UdDIX.jpg