In high-tech fields such as automobiles, electronics and aerospace, plastic cast aluminum parts have gradually become key components due to their advantages such as lightweight, low cost and design flexibility. However, the coordinated optimization of its conductivity, thermal insulation and structural strength has always been a technical bottleneck. Through material composite, structural design and process innovation, the three can be balanced to meet the needs of complex working conditions.
Functional gradient structures can be formed by embedding conductive plastics or carbon fiber reinforced composites in cast aluminum matrix. For example, a conductive coating (such as nickel-plated carbon fiber composites) is covered on the surface of the part to achieve electromagnetic shielding function; a plastic layer filled with thermal insulation ceramic particles is used inside to block the heat conduction path. This layered design not only ensures structural strength, but also realizes functional zoning.
Thermal insulation performance can be achieved through microchannel structure and phase change material (PCM). Micron-level flow channels are designed inside cast aluminum parts, filled with paraffin-based PCM, and the heat is absorbed by its phase change latent heat. For example, when the temperature rises to the phase change point, PCM changes from solid to liquid, absorbing a large amount of heat without significant temperature increase, thereby maintaining the internal temperature of the part stable.
Drawing on the honeycomb structure or bone bionic design in nature, complex inner cavity structures are generated through topological optimization algorithms. For example, additive manufacturing technology is used to build a porous support structure inside the cast aluminum part, which not only reduces weight but also improves bending strength. At the same time, plastic fillers can further enhance toughness and absorb impact energy.
Embedding metal grids or carbon nanotubes (CNTs) in the plastic layer can significantly improve conductivity. For example, copper grids are embedded in the polyamide (PA) matrix through laser sintering technology to form a conductive path. CNTs, with their high aspect ratio and excellent electrical properties, can achieve high conductivity at low filling levels while maintaining the flexibility of the plastic.
The interfacial bonding strength between plastic and cast aluminum directly affects the overall performance. Using silane coupling agents or nano-coating technology, chemical bonds can be formed at the interface between the two to enhance interfacial adhesion. For example, an aluminum oxide nanolayer is deposited on the surface of cast aluminum to interact with polar groups in the plastic to improve interfacial shear strength.
Two-color injection molding technology can achieve integrated molding of plastic and cast aluminum. For example, the cast aluminum skeleton is first prepared by low-pressure casting, and then the conductive plastic is coated on the outer layer by injection molding to form a "hard core soft shell" structure. This process not only ensures structural strength, but also realizes functional integration.
Predict material properties through multi-scale simulation (such as molecular dynamics, finite element analysis), and combine experimental verification to optimize parameters. For example, simulate the dispersion state of carbon nanotubes in the plastic matrix to guide the selection of dispersants; test the stability of phase change materials through thermal cycle experiments to ensure long-term reliability.
The balance of conductivity, heat insulation and structural strength of plastic cast aluminum parts requires collaborative innovation from multiple dimensions of materials, structures and processes. Functional gradient design, thermal management technology, bionic structure optimization and other means provide a feasible path to solve this problem. In the future, with the breakthrough of technologies such as additive manufacturing and nanocomposites, plastic cast aluminum parts are expected to achieve performance breakthroughs in more high-end fields and promote the development trend of lightweight and functional integration.
