A 0.505-in.-diameter metal bar with a 2-in. gage length l0 is subjected to a tensile test. The following measurements are made in the plastic region: Force (lb) Change in Gage length (in.) (Dl ) Diameter (in.) 27,500 0.2103 0.4800 27,000 0.4428 0.4566 25,700 0.6997 0.4343 Determine the strain-hardening exponent for the metal. Is the metal most likely to be FCC, BCC, or HCP? Explain.