Friction and wear behavior of TiC particle reinforced ZA43 matrix composites

TiC/ZA43 composites were fabricated by XD TM and stirring casting techniques. The tribology properties of the unreinforced ZA43 alloy and the composites were studied by using a block on ring apparatus. Experimental results show that the incorporation of TiC particles improves the microstructure of ZA43 matrix alloy. The coefficient of friction μ and the width of worn groove decrease with the increase of TiC volume fraction φ (TiC). The width of worn groove and μ of the composite during wear testing increase with increasing the applied load. Metallographic examinations reveal that unreinforced ZA43 alloy has deep ploughing grooves with obvious adhesion phenomenon, whereas TiC/ZA43 composites have smooth worn surface. Delamination formation is related to the fatigue cracks and the shear cracks on the surface. [

Interfacial characteristics in CNTs-AgCuTi systems

AgCuTi-based composite fillers reinforced with Carbon Nanotubes(CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy(FESEM), XRay Diffraction(XRD) and a Differential Scanning Calorimeter(DSC). After being heated at 900 ℃, the microstructure of the composite fillers was examined through FESEM and Transmission Electron Microscopy(TEM) to analyze the interfacial characteristics in the AgCuTi-CNTs system.The microstructures of the composite fillers with 0.5 wt% CNTs and 0.1 wt% CNTs were compared. It was found that 0.5 wt% CNTs were favorable for dispersive distribution of the structure.Nano-sized TiC particles formed in the reaction of CNTs with Ti, resulting in the transformation of TiCu;with high Ti content and Ti;Cu;phases to TiCu;phase with low Ti content. Additionally,the microstructure evolution of the composite fillers was studied by changing the ratio of Ti/CNTs.Results showed that CNTs significantly influenced the wettability of the AgCuTi filler. After addition of 0.3 wt% of CNTs, the spreading area of the composite filler on the C/C composite increased by 146.0%.

In Situ TiC/FeCrNiCu High-Entropy Alloy Matrix Composites:Reaction Mechanism,Microstructure and Mechanical Properties

In situ TiC particles-reinforced FeCrNiCu high-entropy alloy matrix composites were prepared by vacuum induction melting method.The reaction mechanisms of the mixed powder(Ti,Cu and C)were analyzed,and the mechanical properties of resultant composites were determined.Cu4Tiwere formed in the reaction of Cu and Ti when the temperature rose to 1160 K.With the temperature further increased to 1182 K,newly formed Cu4Tireacted with C to give rise to TiC particles as reinforcement agents.The apparent activation energy for these two reactions was calculated to be 578.7 kJ/mol and 1443.2 kJ/mol,respectively.The hardness,tensile yield strength and ultimate tensile strength of the 15 vol%TiC/FeCrNiCu composite are 797.3 HV,605.1 MPa and 769.2 MPa,respectively,representing an increase by 126.9%,65.9%and 36.0%as compared to the FeCrNiCu high-entropy base alloy at room temperature.However,the elongation-to-failure is reduced from 21.5 to 6.1%with the formation of TiC particles.It was revealed that Orowan mechanism,dislocation strengthening and load-bearing effect are key factors responsible for a marked increase in the hardness and strength of the high-entropy alloy matrix composites.

Synergistic effects of multiscale TiC and dual-phase structure on tensile properties of particle-reinforced steel

The conventional melting methods were used to obtain in situ TiC particle-reinforced dual-phase steel,followed by hot rolling and heat treatment processes.The aim was to investigate the effect of TiC particles on the fracture behavior of dual-phase steel at different annealing temperatures,by analyzing the microstructure and tensile behavior of the multiscale TiC particle-reinforced dual-phase steel.The results showed that TiC particles precipitated in the as-cast microstructure of dual-phase steel were distributed along the grain boundaries.During hot rolling,the grain boundary-like morphology of the micron-sized TiC particles was disrupted,and the particles became more refined and evenly distributed in the matrix.The tensile tests revealed that the strength of the TiC particle-reinforced dual-phase steel increased with increasing martensite content,while the elongation decreased.These results were similar to those of conventional steel.The addition of 1 vol.%multiscale TiC particles improved the strength of the dual-phase steel but did not affect elongation of the steel.Cracks and holes were primarily concentrated around the TiC particles rather than at the interface of martensite and ferrite.The main causes of crack sprouting were TiC particle interface cracking and TiC particle internal fragmentation.Overall,the study demonstrated the potential of multiscale TiC particle-reinforced dual-phase steel as a strong and tough material.The refined distribution of TiC particles in the matrix improved the strength of the material without compromising its elongation.The results also highlighted the importance of careful selection of reinforcement particles to avoid detrimental effects on the fracture behavior of the material.