The　deformation　activities　near　crack　tips　of　submicron-sized　single-crystalline　Mo　were　investigated　using　in　situ　transmission　electron　microscopy　(TEM)　with　mixed　mode　I-II　loading.　Results　show　that　dislocations　in　multiple　slip　systems　were　activated　in　front　of　crack　tips.　These　dislocations　glided　on　the　uncommon　slip　planes　of　{123},　forming　dislocation　arrays.　These　dislocations　moved　at　velocities　of　3-5　nm/s　with　spacing　of　similar　to　10-34　nm　in　the　zone　of　similar　to　50-300　nm　away　from　crack　tips.　Dislocation　velocity　and　spacing　were　influenced　by　the　force　from　elastic　crack　stress　field.　Additionally,　phase　transformation　from　body-centered　cubic　to　face-centered　cubic　was　also　activated　in　front　of　crack　tips,　and　high　densities　of　interface　dislocations　were　observed　at　the　semicoherent　phase　interfaces.　Two　kinds　of　phase　transformation　mechanisms　were　uncovered.　One　is　the　Pitsch　mechanism,　which　is　rarely　accessed,　while　the　other　is　the　Nishiyama-Wasserman/Kurdjumov-Sachs　mechanism.　(C)　2019　Elsevier　B.V.　All　rights　reserved.