Preparation And Investigation Of 3D-MMCs/steel Composites With Interpenetrating Bi-continuous Structure

For conventional reinforced particles evenly dispersed composite material(MMCs), the interface of ceramic particles and metal matrix is a place where cracks can easily appear and extend. When composites were under strong impact wear condition, the composites may fracture, fall off, and even local material peel off, finely showed the poor wear resistance. The spatial structure of MMCs toughening was proved to be an effective measure to improve it’s plasticity and toughness, which is the key to solve its resistance to strong impact abrasion working conditions. the so-called space structure toughening MMCs are divided into uniform distribution in the space of reinforcing particles enrichment composite region (area) (brittle) and pure substrate area (toughness area). It’s difficult to control the shape and size when prepare space structure composites, lead to be less related research,3D printing+ pressure impregnation technique was used to prepare MMCs and steel composite with three dimensional interpenetrating network structure (3D-MMCs/steel) in this paper.This paper focus on exploring the composition design (ZTA reinforcing particles, 40Cr steel substrate, the PLA fused deposition type 3D printing materials) and structural design (tetragonal packing structure, ball packing structure) and the preparation process of composites. Scanning electron microscope、metallographic microscope、energy spectrometer、vickers hardness tester were used to studied the composites.The bending properties and impact abrasive wear properties of 3D-MMCs/steel composites were investigated and compared with conventional reinforced particles evenly dispersed composite material.Experimental results show that the way of preparation of 3D-MMCs/steel composites with interpenetrating bi-continuous structure is feasible, both the MMCs area and pure substrate area show fine, MMCs area ZTA ceramic particles dispersed evenly, the interface adhesive residue of ZTA/steel in MMCs area is not obvious, and the interface combination belongs to the mechanical combination.3D-MMCs/steel composite material after heat treatment, crack initiation extended to pure substrate from the MMCs area, stop in the area of pure substrate.3D-MMCs/steel composites with 4wt.% sodium silicate:tetragonal piled up, the ball piled up 3D-MMCs/steel composite material three point bending are in stepped down, the stress-strain curve show the obvious pseudoplasticity. Tetragonal piled up 3D-MMCs/steel composite bending strength than conventional reinforcing particles evenly dispersed composites increased by 74.03%, to 652.91 MPa; Deflection increased by 60.10%, the fracture strain reached 6.10%. Ball piled up 3D-MMCs/steel composite bending strength than conventional reinforcing particles evenly dispersed composites increased by 31.03%, to 491.61 MPa; Immunity improved 135.96%, the fracture strain reached 8.99%.3D-MMCs/steel composite material with 5wt.% of aluminum dihydrogen phosphate:tetragonal piled up, ball piled up 3D-MMCs/steel composite material three point bending stress-strain curves are similar to conventional reinforced particles evenly dispersed composite no stepped down.The three point bending turned out that MMCs area continuous and pure substrate area plane is the mechanical properties weak plane.Ball piled up structure 3D-MMCs/steel composite material volume wear rate than the reinforced particles evenly dispersed composite decreased by 31.24%, MMCs area continuous, pure matrix discrete surface than MMCs discrete continuous surface wear-resisting, pure matrix area.