The change in solidification mode and phase composition in "321 stainless Steel/NiCr Alloy" joint produced by Wire-feed electron beam melting.

The influence of variation of Ni content on solidification mode, phase composition and microstructure in additively-manufactured (AM) "321 stainless steel/NiCr alloy" joint has been investigated. The typical for additively-manufactured CrNi stainless steel two-phase (γ+δ) microstructure observed in the "321-SS" area passes into the pure γ-austenite structure when it is stabilized by nickel in the joint "321-SS/NiCr alloy" of the AM billet. The gradual increase in of Ni-concentration in the joint region is accompanied with progressive decrease the value of the Creq/Nieq ratio and alteration of the phase composition and microstructure of the steel part. The change in the primary solidification mode from ferrite into austenite mode occurs in the joint "321-SS/NiCr alloy" when the Creq/Nieq ratio value becomes below the critical one. [ABSTRACT FROM AUTHOR]