Mechanism of hot crack propagation and prevention of crack formation during electron beam powder bed fusion of a difficult-to-weld Co-Cr-Ni-W superalloy

•Cyclic growth of cracks during EBPBF of a difficult-to-weld alloy has been revealed.•Crack-healing, liquation cracking, and hot tearing in a scan cycle have been shown.•Horizontally grown dendrite layer results in crack-free surface.•It is possible to utilize horizontally grown dendrites to prevent crack hot cracking.