W-based　composites　with　the　different　immiscible　second　phases　(Cu　and　Cu10Sn)　were　prepared　by　laser　powder　bed　fusion　(LPBF).　The　immiscible　W　phase　and　Cu/α-Cu　phases　were　prone　to　separate　during　LPBF.　The　melted　W　phase　could　easily　fuse　together　and　form　W　matrix,　and　Cu　or　α-Cu　phase　distributed　within　the　gaps　among　W　phase.　Cu　or　α-Cu　phase　can　provide　a　gradient　cooling　way　for　the　solidification　of　W　phase　through　the　transformation　of　‘solid-liquid-gas’　during　LPBF.　The　evaporation　of　Cu　or　Sn　accelerated　the　heat　dissipation,　which　caused　the　grain　refinement　of　W.　Higher　thermal　conductivity　of　Cu　than　α-Cu　leads　to　the　relative　finer　grain　size　of　W　phase　in　W-Cu　composite.　The　heat　conduction　direction　between　W　phase　and　Cu/α-Cu　also　affected　the　grain　morphology.　Heat　continued　transferred　from　W　to　Cu/α-Cu　induced　the　columnar　grain　growth　of　W,　the　interlacing　distribution　of　W　and　Cu/α-Cu　made　the　growth　of　W　columnar　grains　radiate　out　from　the　center　Cu/α-Cu　phase.　Remarkable,　cracks　were　severely　restrained　in　W　phase　simultaneously　although　W　phase　melted　completely.　This　is　not　only　related　to　improvement　of　strength　and　ductility　of　W　caused　by　grain　refinement,　but　also　because　of　the　interlacing　distribution　of　W　and　Cu/α-Cu　phases,　which　could　effectively　reduce　the　stress　degree　in　W　phase　during　LBPF.　©　2022　Elsevier　B.V.