Mechanical Properties of Ti3AlC2/Cu Composites Reinforced by MAX Phase Chemical Copper Plating

Abstract

Among the various reinforcement phases available in Cu-based composites, the unique layered structure and easy diffusion of A-layer atoms make MAX phases more suitable for reinforcing a copper matrix than others. In this study, Cu-coated Ti3AlC2 particles (Cu@Ti3AlC2) were prepared through electroless plating, and Cu@Ti3AlC2/Cu composites were fabricated via vacuum hot-press sintering. The phase composition and microstructure of both Cu@Ti3AlC2 powder and composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results demonstrate the creation of successful electroless copper plating to obtain a Cu coating on Ti3AlC2 particles. At 850 °C, a small amount of Ti3AlC2 particles decompose to form TiCx, while Al atoms from the A layer of MAX phase diffuse into the Cu matrix to form a solid solution with Cu(Al). The test results reveal that the density of the Cu@Ti3AlC2/Cu composite reaches 98.5%, with a maximum compressive strength of 705 MPa, which is 8.29% higher than that of the Ti3AlC2/Cu composite. Additionally, the compressive strain reaches 37.6%, representing an increase of 12.24% compared to that exhibited by the Ti3AlC2/Cu composite.

Physical Mechanism of Nanocrystalline Composite Deformation Responsible for Fracture Plastic Nature at Cryogenic Temperatures

“…The graphic dependence curves in Figure 3 show that the composite compound of nanocrystalline/amorphous film–fusible alloy retains the plastic character of destruction when the test temperature decreases to 77 K. This may be related to the fact that the crack growth in the composite is accompanied by local heating, whereby the area at the top of the crack heats up as a result of plastic deformation. This effect has been previously considered theoretically in [ 16 ] and is known as the “free volume” model. The model was proposed by Spapen; the plastic deformation of amorphous metal alloys is based on the concept of free volume.…”

“…There is no regular crystal lattice in amorphous materials, so the atoms are randomly distributed. Within the framework of the “free volume” model, it is assumed that plastic deformation occurs due to a series of atomic jumps to the location of a single free volume [ 16 ]: where is the yield strength, is the deformation rate, is the height of the potential barrier for the movement of dislocations, is the Boltzmann constant, is the activation volume, and .…”

“…There is currently no uniform view on the mechanism of heterogeneous plasticity of nanocrystalline/amorphous materials and layered composites based on them [ 16 ]. The interface of the layered structures is known to have a significant influence on the mechanical properties of nanomaterials due to its complicated microstructure.…”

“…Taking into account the above-discussed theoretical concepts based on the analysis of physical phenomena [ 16 , 36 , 37 , 38 , 39 , 40 ] describing the fracture process in a nanocrystalline/amorphous material, a physical model of the heating of the region in the vicinity of the crack tip was formulated. The heat transfer by the mechanism of thermal conductivity with internal heat sources in the investigated solid material is described by the differential equation of thermal conductivity (Fourier differential equation).…”

“…In the case of amorphous metal alloys, the deformation pattern changes from homogeneous to heterogeneous as the temperature decreases. Microhardness and yield strength for amorphous metal alloys can be divided into thermal and non-thermal components, the non-thermal component depending on the chemical composition and crystal lattice, while the temperature dependence of microhardness is not affected practically by the structural and chemical composition [ 16 ].…”