wherein the damaged location of the region near the surface contains {HEAD ~ a degradation} of {TAIL ~ a microstructure} whereby that at least a specific microstructural portion falls below a required concentration, 
of
wherein the damaged location of the region near the surface contains { HEAD ~ a degradation } of { TAIL ~ a microstructure } whereby that at least a specific microstructural portion falls below a required concentration ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH