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