An additive manufacturing process comprising directed-energy deposition and pre-depositing interface metal layers

A directed-energy deposition process to build a metal article (10), using directed-energy deposition of deposited layers (7) comprising feeding metal feedstock (3) into a focus (2b) of thermal energy (2a) onto an underlying target surface portion (5a) along a tool path, to create a layer (7) of deposited metal material, creating successive layers (7) of deposited metal material by vertically with respect to the deposition plane moving the deposition head (1) on each previous layer (7) of deposited metal material whereby at least one of a first density of the metal feed feedstock and a first specific thermal energy generated by the thermal source provides a specific consistency of each deposited layer and a specific bonding strength thereof to the underlying target surface. The process further comprises providing at least one interface metal layer (9) between an underlying target surface portion (5a) and a successive layer (7) of deposited metal material, by applying a reduced specific energy and an increased density of the metal feedstock (3), so that the metal material of the interface metal layer (9) does at the most only partially fuse with the surface portion (5a) of the substrate (5), to obtain bonding of a reduced strength between the metal interface metal layer (9) and the substrate (5), and to confer to the interface metal layer (9) a higher brittleness, and a decreased bonding to the underlying target surface (5a).