Such materials include metals such as an aluminum alloy or stainless steel, {HEAD ~ a polymer} such as Acetal and {TAIL ~ composites} 
such as
Such materials include metals such as an aluminum alloy or stainless steel , { HEAD ~ a polymer } such as Acetal and { TAIL ~ composites }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL