So the redesigned blades failed due to creep?
From what little you said was the redesigned blade less efficient such that they were required to hotter to achieve the required rotating speed ?

Yes, we ran a thick wire through each blade at mid height, all the way round, to damp out vibrations by friction damping. I beefed up the blade to compensate for the loss of cross section at the hole, and for the extra CF load from the wire, but no one realised until after the big bang (on the test bed) that extra fuel/heat would be required because the wire lowered the turbine efficiency. Hindsight is 20/20 vision.