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