Investigation On Interface Structure And Mechanical Properties Of Laminated Aluminum Matrix Composites

The laminated aluminum matrix composites is a multilayer material formed by alternately overlapping aluminum substrates and component materials at a certain layer distance and layer thickness ratio.Component materials can be metals,ceramics,intermetallic compounds,or polymers,and the properties of the material depend on the structure and characteristics of each component,their respective volume content,layer spacing,mutual solubility,and brittleness between the two components Intermetallic compounds.Because laminated aluminum matrix composites have a layered structure that can be designed,they can meet multiple performance requirements and structural requirements,and they have received widespread attention in various fields rencently.This paper studies the effects of two types of reinforcements on the interface structure and mechanical properties of aluminum-based laminated materials,laying the foundation for the preparation of new lightweight and high-performance laminated aluminum matrix composites.In this paper,10 ?m pure aluminum foil is selected as the matrix,and B4C powder and pure titanium foil are used as the reinforcing phase.After the two reinforcing phases are stacked with the aluminum foil layer by layer,the Al/B4C and Al/Ti laminated composite materials are finally obtained through accumulative fold pressing and spark plasma sintering.The main research contents are as follows.The effects of accumulative fold pressing cycles on the interface structure and mechanical properties of Al/B4C laminated materials were studied.The results show that:with the increase of accumulative fold pressing cycles,the thickness of the aluminum layer continues to decrease,and the state of the B4C particles at the interface changed from agglomeration and continuous distribution along the interface to a single-layer particle continuous distribution along the interface,and then the aluminum layer was squeezed into the gap between the B4C particles and then turned into discrete B4C particles intermittently distributed on the interface.When the accumulative fold pressing cycles does not exceed 5 times,the sample has a clear layered structure,when the accumulative fold pressing cycles is 7 times,the layered structure is not obvious.As the accumulative fold pressing cycles increases,the compression strength and hardness are significantly improved.At low accumulative fold pressing cycles,the mechanical properties of the Al/B4C laminated material are anisotropic in parallel and perpendicular directions,and anisotropy gradually disappears at high cycles.The changes in the interface structure and mechanical properties of Al/Ti laminated materials during spark plasma sintering and pressureless diffusion were studied.The results show that:under the sintering process of 500?,50MPa and 30min,the metallurgical bonding between the interfaces is weak,and the compression performance of the sample in the direction of parallel layers is poor.After 600? pressureless diffusion treatment,an Al3Ti phase was formed between the Al/Ti interface,the compressive strength increased,plastic drop.During the compression process of the laminated material in the direction of the perpendicular layer,a 45° fracture zone appeared,titanium layer was sheared during the compression process,aluminum layer was squeezed into the fracture zone.Many small cracks were generated in the Al3Ti layer,cracks are dense in areas near the fault zone,cracks are gradually reduced in areas far from the fault zone,and energy is gradually dissipated along the layer direction.As a result of compression in the direction of the parallel layer,it was found that cracks initiated and propagated in the Al3Ti layer,and then caused fracture.Comprehensive analysis shows that:both types of reinforcing materials increase the strength of the matrix material,but the way to strengthen the matrix is different.After accumulative fold pressing of Al/B4C laminated material,the B4C powder is discretely,intermittently distributed on the interface,and is surrounded by the aluminum layer.Under the influence of external force,it cooperates with the aluminum layer to deform together to improve the deformation resistance of the substrate,so that the strength has been improved;the Al/Ti laminated material generates an Al3Ti layer through a diffusion reaction.Al3Ti is hard and brittle,and provides the strength in the stack,the unreacted aluminum and titanium layers provide plasticity,the soft-hard alternating laminated structure makes the material have a structure of energy dissipation,so that the mechanical properties of the laminated layer are improved.