The　Al-5.9Cu　metal　target　was　impacted　by　armor-piercing　incendiary　at　different　impact　velocities.　At　velocity　of　495　m/s,　some　parts　of　grain　boundaries　showed　serrated　heaves　near　the　crater　bottom,　and　two　kinds　of　deformed　bands　were　formed.　The　one　looked　like　slip　bands,　the　other　was　paralleled　to　the　direction　of　flow　pattern.　There　were　shear　bands　and　tearing　damages　near　the　crater　wall.　Whirlpool-like　shear　bands　and　helical-like　shear　bands　in　the　region　around　crater　were　produced　by　high　velocity　impact.　Plenty　of　microbands　near　the　craters　were　observed　at　the　two　different　velocities.　A　possible　microband　formation　mechanism　is　proposed　by　extending　the　HNANG　model.　The　model　involves　the　spread　of　impact　waves,　the　generation　of　polarized　dislocation,　the　annihilation　of　dislocation　in　the　middle　of　the　bands,　the　formation　of　secondary　dislocation　and　so　on.