Niobium carbide reinforced manganese steel

Abstract

A composite material has at least one reinforcing zone including niobium carbide (NbC) and a manganese steel matrix. A manganese steel zone surrounds the at least one reinforcing zone and an interface layer is positioned between the reinforcing zone and the manganese steel zone. An average grain size of the NbC particles in the at least one reinforcing zone is between 2-5 μm.

1 . A composite material comprising:
 at least one reinforcing zone including niobium carbide (NbC) and a manganese steel matrix;   a manganese steel zone surrounding the at least one reinforcing zone; and   an interface layer positioned between the reinforcing zone and the manganese steel zone, wherein an average grain size of the NbC in the at least one reinforcing zone is between 2-5 μm.   
     
     
         2 . The composite material according to  claim 1 , wherein the wt % of NbC in the at least one reinforcing zone is between 60-98. 
     
     
         3 . The composite material according to  claim 1 , wherein a composition of the manganese steel in the manganese steel zone has the chemical composition by weight of:
 carbon: 0.5 to 2.0%;   manganese: 11 to 22%;   silicon: 0.2 to 1.0%;   chromium: 1 to 2%;   nickel: up to 0.6%;   molybdenum: up to 0.5%;   and a balance of iron.   
     
     
         4 . The composite material according to  claim 1 , wherein a hardness of the at least one reinforcing zone is between 600-1000 HV1 and the hardness of the manganese steel zone is between 200-300 HV1 before work hardening. 
     
     
         5 . The composite material according to  claim 1 , wherein a thickness of the interface layer is between 90-295 μm. 
     
     
         6 . The composite material according to  claim 1 , wherein the interface layer  8  is free of defects. 
     
     
         7 . The composite material according to  claim 1 , wherein wettability between the NbC grains and the manganese steel in the at least one reinforcing zone is >99%. 
     
     
         8 . The composite material according to  claim 1 , wherein the at least one reinforcing zone has a volume of between 30-75 cm 3 . 
     
     
         9 . The composite material according to  claim 1 , wherein at least 90% of the NbC grains in the at least one reinforcing zone has a square prismatic shape, wherein a square prismatic shape is a cuboid having two square faces and two rectangular faces, 12 edges and 8 vertices and wherein a percentage of grains having the square prismatic shape is calculated by counting from a SEM fracture surface image. 
     
     
         10 . The composite material according to  claim 1 , wherein there are a plurality of reinforcing zones and a distance between two neighbouring reinforcing zones is between 1-5 mm. 
     
     
         11 . A wear part comprising the composite material according to  claim 1 . 
     
     
         12 . A method of producing a composite material according to  claim 1 , the method comprising the steps of:
 a) mixing together 50-90 wt % niobium, 6-20 wt % carbon and 0-40 wt % catalysis powders;   b) compacting the mixed powders together to form at least one compact;   c) positioning and optionally fixing the at least one compact into an interior of a mold;   d) pouring molten casting manganese steel into the mold to surround the at least one compact to initiate a self-propagating high temperature synthesis reaction to produce a cast;   e) heat treating the cast; and   f) quenching the cast, wherein in step b) the powders are compacting with a pressure of between 450-700 MPa.   
     
     
         13 . The method according to  claim 12 , wherein the catalysis is selected from iron, cobalt, nickel, molybdenum, chromium, tungsten, aluminum, or a mixture thereof.