Friction-rolling　additive　manufacturing　(FRAM)　is　an　innovative　solid-state　additive　manufacturing　method　for　＂non-weldable＂　alloys.　The　basic　physics　of　this　method　relies　on　a　rotating　toolhead　to　generate　severe　plastic　deformation　and　thereby　deposit　the　material.　However,　the　specific　processes　of　heat　generation　and　material　flow　behaviors　induced　by　the　rotating　toolhead　are　not　fully　understood.　In　this　study,　a　novel　three-dimensional　thermomechanically　coupled　Eulerian-Lagrangian　model　with　a　particle　tracing　technique　was　developed　to　analyze　the　transient　temperature　evolution　and　material　flow　behaviors　during　FRAM.　The　nu-merical　simulation　was　validated　based　on　experimental　temperature　measurements　and　the　geometry　of　the　deposit.　The　heat-generation　process　and　gradual　stabilization　of　the　temperature　field　during　the　three　stages　of　FRAM--namely,　toolhead　insertion,　material　feeding,　and　toolhead　advancement--were　successfully　charac-terized.　The　results　show　that　the　toolhead　simultaneously　generates　heat　in　the　material　strip　and　substrate,　and　more　heat　is　generated　in　the　shoulder　and　the　transition　zone　where　the　toolhead　shape　changes　from　concave　to　convex.　The　presence　of　a　single　shoulder　leads　to　an　asymmetrical　temperature　distribution　along　the　axial　direction　(Y　direction)　of　the　toolhead.　The　material　near　the　toolhead　flows　tangentially　around　the　toolhead,　and　the　flow　of　the　strip　is　better　than　that　of　the　substrate.　The　particle　tracing　results　show　that　the　strip　and　substrate　surfaces　are　well-mixed　in　the　Z　direction　under　the　rotating　action　of　the　toolhead.　The　findings　from　this　study　can　be　applied　in　further　fundamental　investigations　of　the　FRAM　process　and　toolhead　morphology　design.