A　laser　keyhole　welding　process　was　performed　to　join　of　6mm　thick　aluminum　(Al)　alloys　to　steel　plates　in　a　butt　configuration　without　any　filler　materials.　High　quality　metallurgical　bonding　joints　were　produced　by　controlling　welding　parameters.　The　effect　of　different　laser　beam　effsets　and　different　locations　of　joints　on　the　morphology,　phase　components　and　thickness　of　the　intermetallic　compound　(IMC)　layers　was　investigated　by　using　optical　microscope　(OM)　and　electron　backscatter　diffraction　(EBSD)　analysis　technology.　The　results　show　that　the　main　phases　of　IMC　layers　are　composed　of　η-Al5Fe2　and　θ-Al13Fe4　phases.　The　laser　beam　offsets　have　an　important　influence　not　only　on　the　average　thickness　of　IMC　layers　but　also　on　the　IMC　grain　size:　increasing　laser　beam　offsets　significantly　reduces　the　amount　of　needle-like　θ-Al13Fe4　phases,　refines　the　grain　sizes　of　η-Al5Fe2　layers,　and　decreases　the　average　thickness　of　η-Al5Fe2　layers　at　the　interfaces.　In　considering　the　influence　of　the　different　locations　through　the　steel/Al　alloy　joint,　under　the　conditions　of　two　laser　beam　offsets,　the　minimum　grain　size　and　thickness　of　η-Al5Fe2　layers　have　been　obtained　at　the　middle　part　of　the　steel/Al　alloy　joints.　In　addition,　it　shows　clearly　that　the　θ-Al13Fe4　phases　are　generated　between　the　η-Al5Fe2　layers　and　the　steel　substrates　are　confirmed　by　the　EBSD　phase　analysis.　©　2018,　Journal　of　Materials　Engineering.　All　right　reserved.