Effect of carbon, silicon, iron, and tungsten on the structure and phase composition of alloy N70KhM

1. The structure and phase composition of nickel-chromium-molybdenum alloys of the 15 Cr-15 Mo system quenched in watr from 1200°C and aged at 800–1000°C depend on the concentration of carbon, silicon, iron, and tungsten. 2. In alloy N70KhM with 0.03% C and 0.06% Si particles of dispersed intermetallic phase, probably P or N phase, are observed along with M6C carbide in the grain boundaries and boundary areas. 3. In the N70KhM alloy with 0.04% Si carbon induces the formation of M6C carbide with a lattice constant of 11.06 kX. 4. In the N70KhM alloy with 0.03% C silicon induces precipitation of cubic M6C carbide with a lattice constant of 10.86 kX in the grain boundaries; on prolonged heating a hexagonal phase of the AB2 type is also precipitated in the grain boundaries and within the grains. 5. In the N70KhM alloy with 0.03% C and 0.06% Si tungsten induces precipitation of M6C carbide in the grain boundaries and hexagonal μ-phase of the Co7Mo6 type in separate sections of the boundaries and boundary areas; nickel, chromium, molybdenum, and tungsten enter into its composition. 6. Alloying of N65KhMV with both silicon and iron induces precipitation of μ-phase of the Co7Mo6 type, into the composition of which enter nickel, molybdenum, chromium, and tungsten, and also silicon and iron.