Insight to agglomeration and chemical reactions of CoAl2O4 inoculants in IN718 processed by selective laser melting

•Agglomeration of CoAl2O4 inoculants follows the scan direction.•Modifying the scan speeds and energy densities can inhibit the agglomeration.•CoAl2O4 was reduced within the melt pool to from Co-rich particles.•The extent of melt pool remelts the Co-rich particles present in deposited layers.•Insufficient energy input may lead to a slight fraction of unreacted CoAl2O4.