Development of the metal-sand composite casting method using polymer patterns in the context of modern composite materials systematization

Abstract

In the context of the dynamic development of Composite Materials (CMCs), their scientific systematization is critically necessary, as traditional classification approaches are insufficient for effectively predicting operational properties during the design of such materials. The first part of the work presents a multi-factor, multi-level CMC systematization scheme. This block diagram reflects the interrelation of technological, structural, and functional aspects of material creation, serving as a methodological basis for positioning research objects within the modern system of materials science. Based on the systematization, a method for casting Metal-Sand Cast Composite Materials (LCMCs) using the Lost Foam Casting (LFC) process was developed. The goal was to overcome the limitations of the LFC process in obtaining structural CMCs with closed, non-metallic, filled cells, and to reduce production cost by optimizing core tooling. The essence of the innovation is the fundamentally new use of the polymer pattern as a combined molding and core tooling (carrier). The pattern is used to form sand cores from a sand-liquid glass mixture (CO₂-process), which are held in the mold and remain in the LCMC body. This eliminates the need for expensive traditional core tooling, significantly increasing the economic efficiency of the process. The developed method utilizes thin-walled polymer shells made from Expanded Polystyrene (EPS), PLA by 3D printing, or thermoforming. The feature utilized is that for printed patterns, gas-forming capacity can be regulated by changing the wall thickness and using the integrated sand core as an internal spacer. The resulting metal-sand composite (cores with a density of 1.6…2.0 g/cm³ in a matrix with a density of >7.0 g/cm³) shows a significant reduction in the product's mass without loss of strength. Accelerated metal crystallization due to reduced wall thickness promotes the formation of a fine-grained, high-strength structure. The reinforcement provides the casting with additional functional properties, particularly increased resistance to impulsive penetrating destruction, which is critical for anti-armor obstacles and protective structures. The method is technologically flexible, allowing for the production of both metal-sand CMC and a hollow metallic cell-framework product. The technology is designed for the development of lightweight modules for the rapid construction of protective structures.