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