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The short carbon fiber orientation changes with the pressure direction during the sintering process, which strongly influences the mechanical and wear performance of short carbon fiber and ZrC strengthened 2024Al matrix composites (C f (Ni)-ZrC/2024Al). The C f (Ni)-ZrC/2024Al composite parallel to the carbon fiber plane (C f (Ni)-ZrC/2024Al-P) shows higher elastic modulus, tensile strength, and strain, which has 17.1 %, 21.58 %, and 25.42 % increases respectively compared with the C f (Ni)-ZrC/2024Al composite vertical to the carbon fiber plane (C f (Ni)-ZrC/2024Al-V). In C f (Ni)-ZrC/2024Al-P, the carbon fibers mainly fail by pulled-out behaviors, which can expend more fracture energy and lengthen the propagation path of cracks compared with the primary debonding behavior of the carbon fibers in C f (Ni)-ZrC/2024Al-V. The wear rates of the C f (Ni)-ZrC/2024Al-P and C f (Ni)-ZrC/2024Al-V are improved with the load, while the coefficient of friction shows the contrary tendency. The C f (Ni)-ZrC/2024Al-V is more wear resistance but less anti-friction than that of C f (Ni)-ZrC/2024Al-P. In C f (Ni)-ZrC/2024Al-P, the carbon fiber plane is parallel to the worn surface, which leads the carbon fiber to be swept out easily as a whole owing to the absence of the gripped aluminum matrix and the parallel plane between the friction force and interface. It causes the cracks to propagate along the interface easily and hardly form a steady MML. • C f (Ni)-ZrC/2024Al composite parallel to the carbon fiber plane shows higher tensile strength and strain. • The wear rates of the composites are increased with the applied load regardless of the orientation of the carbon fiber. • The C f (Ni)-ZrC/2024Al composite vertical to carbon fiber plane shows better wear resistance. [ABSTRACT FROM AUTHOR]

In this paper, the aging behavior of Cf(Ni)-ZrC/2024Al composites with a quasi-network structure was studied carefully. The microstructure observation exhibits that the ZrC particles, carbon fibers, and Al matrix form a good interface bonding. The interfacial phase between the carbon fiber and Al matrix exhibits good thermostability during solution and aging treatment. With the addition of carbon fibers and ZrC particles, the composites only take 8 h to reach peak-aged condition while in monolithic 2024Al alloy, it needs 12 h. The peak-aged hardness of the composites is 136.4 HV, having 15.2% increments than 2024Al (118.4 HV). The yield, tensile strength, and strain of the peak-aged composites are 350.5 MPa, 536.4 MPa, and 14.8% respectively, which are improved by 56.5%, 45.8%, and 52.6% compared with 2024Al. The yield and tensile strength of composites are increased with time going by until they reach a peak aging state, agreeing well with that of hardness. The TEM observations of precipitated phases demonstrate the size and number of Al 2 Cu and Al 2 CuMg present a similar variation tendency. The improved tensile property of the composites is mainly due to pulled-out carbon fibers, quasi-network structure, outstanding interface bond, and precipitate strengthening. • The Cf(Ni)-ZrC/2024Al composites only take 8 h to reach to peak-aged condition, while the 2024Al needs 12 h. • The yield, tensile strength and strain of the composites are significantly improved compared with the 2024Al. • The improved strength is due to pulled-out carbon fiber, quasi-network structure, good interface bond and fine precipitate. [ABSTRACT FROM AUTHOR]

• The 2024Al matrix composites reinforced with bimodal-scaled reinforcements of carbon fibers and ZrC particles, were successfully fabricated by spark plasma sintering. • The interfacial bonding strength was improved by plating Ni-P coating on the carbon fibers. • The C f (Ni)-ZrC p /2024Al composites with the quasi-network architecture have a remarkable increase in the tensile strength and ductility. The 2024Al matrix composite reinforced with bimodal-scaled reinforcement phases, carbon fibers and ZrC particles, was designed and prepared by spark plasma sintering for the purpose of obtaining high strength and good ductility. The microstructural observation shows that the ZrC particles mixed with the Al 2 Cu and Al 2 CuMg precipitate phases formed a quasi-network architecture. The Ni coating electroless plated on the carbon fiber can improve the interfacial bonding strength by the chemical reactions of Ni-P coating and matrix as well as prevent the reaction of carbon fiber and 2024Al. As expected, the tensile strength and ductility of bimodal-size reinforced composites with peculiar quasi-network structure showed a significant improvement in comparison with the 2024Al matrix alloy and monolithic carbon fibers or ZrC particles reinforced composites. The 2024Al matrix composites strengthened with carbon fibers and ZrC particles exhibit the tensile strength and elongation of 330 MPa and 10.2%, which are 39.2% and 229% higher than the 2024Al matrix. The excellent enhancement effect is owing to load transfer effect, quasi-network structure strengthening, precipitation refinement, Orowan strengthening as well as dislocation strengthening. [ABSTRACT FROM AUTHOR]

Hybrid (Ti 5 Si 3 + TiC x) (x = 0.67) particles reinforced TC4 matrix composites were in-situ prepared by hot-press sintering, basing on the reactions between Ti 3 SiC 2 and Ti. To research the effects of Ti 3 SiC 2 content on the microstructures and mechanical properties, 1–10 wt% Ti 3 SiC 2 were selected. When Ti 3 SiC 2 content was less than 5 wt%, Si element dissolved in the matrix, and TiC x distributed in the matrix homogeneously. While the content exceeded 5 wt%, Si was precipitating as Ti 5 Si 3 attaching to TiC x particles, which resulted in the aggregations of reinforcements. The micro-hardness of matrix was improved with the solid solubility of Si increasing in matrix, and the compressive strength was improved with Ti 3 SiC 2 content increasing. The hardness was mainly affected by solid solution strengthening. The compressive strength was affected by the solid solution strengthening, fine-grain strengthening and the improvement effect of reinforcements. It was determined that solid solution strengthening played the major role by theoretical calculation. • In-situ preparing (Ti 5 Si 3 +TiC 0.67)/TC4 composites for the first time. • Ti 5 Si 3 particles is prone to attach the TiC 0.67 particles. • Solid solution strengthening dominate the improvement of mechanical properties. [ABSTRACT FROM AUTHOR]

Cr 3 C 2 -20 wt % Ni cermets were prepared by Cr, C and Ni mixed powders using high energy milling and reactive sintering method comparing with the one contains 1 wt % Mo addition. Isothermal oxidation experiments were conducted at 800 °C in the static air from 10 h to 100 h using cyclic oxidation method. The high temperature oxidation behavior of Cr 3 C 2 -20 wt % Ni cermets effected by 1 wt % Mo addition was investigated. After 100 h oxidation, the oxidation weight increase and parabolic rate constants of the one with Mo decreased from 0.126 to 0.080 mg/cm 2 and 4.41 × 10 −12 to 1.78 × 10 −12 kg 2 /m 4 ·s, respectively. Generally, two positive effects were found by Mo additive, such as increasing the Cr atom concentration in the Ni and minimizing the formation of NiO during oxidation. The oxidation products of the cermets changed from forming the Cr 2 O 3 and NiCr 2 O 4 to that only forming Cr 2 O 3 after adding molybdenum element. Pure Cr 2 O 3 possessed better and denser crystal structure than that of NiCr 2 O 4 . The cermets were protected due to the formation of the dense oxide films on the surfaces of the substrates at high temperature. This novel mechanism was of academic influence and could serve as a guide for the further research on Cr 3 C 2 - 20 wt % Ni cermets. [ABSTRACT FROM AUTHOR]

Nanostructural Y-Zr-O oxide dispersion-strengthened (ODS) Mo alloys were in-situ prepared based on the dissolution and re-precipitation strategy of oxides during mechanical alloying (MA) and spark plasma sintering (SPS). The effect of Zr addition on the microstructures and mechanical properties of Mo-1Y 2 O 3 -xZr alloy (x = 0.3, 0.6, 0.9, and 1.2 wt%) was investigated. The results show that both intragranular and intergranular Y-Zr-O particles are nanoscale and non-stoichiometric, possessing a different Y/Zr ratio. The Y-Zr-O particles and ultrafine grain structure jointly contribute to high strength (1.87 times over pure Mo) and simultaneously great elongation (2.98 times over pure Mo) of Mo-1Y 2 O 3 -0.3Zr alloy. The yield strength and elongation are reduced as Zr addition beyond 0.6 wt%, owing to the aggregation of Y-Zr-O particles at grain boundaries. The theoretical calculation indicates that the strength is mainly affected by grain refinement strengthening and Orowan precipitate strengthening. But the strength is less predicted due to a great amount of Y-Zr-O nanoclusters smaller than 5 nm cannot be considered in the statistical analysis by conventional TEM. • In-situ preparing nanostructural Y-Zr-O oxide dispersion-strengthened (ODS) Mo alloys byMA and SPS. • Nanoscale intragranular and intergranular Y-Zr-O oxides and ultra-grained structure jointly improved mechanical properties. • Grain refinement strengthening and Orowan precipitate strengthening dominate the improvement of strength. [ABSTRACT FROM AUTHOR]

Highlights: [•] FeNi3@C nanowires have been synthesized by a facile hydrothermal method. [•] FeNi3 nanowires have diameters ranging from 5 to 15nm. [•] The coexistence of natural resonance and exchange resonance result in magnetic loss. [•] The FeNi3@C nanowires can be a potential material for fabricating microwave devices. [ABSTRACT FROM AUTHOR]

In this work, the effect of Sb addition on the microstructure and mechanical properties of Mg 2 Si phase in Mg 2 Si/AZ91 composites are investigated by experimental research and first-principles calculation. The experimental results show that the coarse dendritic shape is modified to blocky polygonal shape, and the size of primary Mg 2 Si, is successfully refined with the Sb addition. With enhancing Sb addition contents, the doping concentration of Sb in Mg 2 Si phase keeps increasing, which accounts for the morphology and size modification. Besides, nano-indentation tests reveal that the Young's modulus of Mg 2 Si phase exhibits less reduction, while the hardness is significantly improved when introducing 2.0 wt%Sb. The calculated results indicate that the structure stability of Mg 2 Si crystal is enhanced, and the mechanical modulus including bulk modulus, shear modulus and Young's modulus of Mg 2 Si are decreased with the increase of Sb concentration, agreeing well with experimental observation, but the hardness reduces, which is contrary to the experimental results. Mg 2 Si phase doping with Sb atoms, however, exhibits improved ductile behavior compared with undoped Mg 2 Si due to the increased Poisson's ratio and B/G ratio. In addition, Sb doping can weaken the bond strength and reduce the population of Mg-Si covalent bonds, as well as generate new Mg-Sb bonds with lower strength based on the electronic structure analysis, which contribute to the decrease of mechanical modulus. • The morphology of Mg 2 Si is modified with increasing Sb. • Sb doping reduces Young's modulus but enhances the hardness of Mg 2 Si. • The structure stability of Mg 2 Si crystal is enhanced by Sb doping. • Sb doped Mg 2 Si exhibits reduced mechanical modulus and improved ductility. • Newly formed Mg-Sb covalent bonds account for evolution of mechanical properties of Mg 2 Si. [ABSTRACT FROM AUTHOR]

• Multi-phase nanocores consist of Sn, FeSn 2 and FeO nanoparticles. • The shell is made of amorphous N-doped carbon. • Enhanced properties are due to the synergetic effects. • Synergy of multiphase cores, in-depth nanocrystallization and C shell confining. [Display omitted] A two-step approach using co-precipitation and thermal reduction treatment strategy is adopted to synthesize Sn/FeSn 2 /FeO@nitrogen-doped carbon yolk-shell nanocubes with multi-phase nanocores for highly stable anode materials in lithium-ion battery. In the novel yolk-shell nanostructure, the multi-phase nanocores consist of Sn, FeSn 2 and FeO nanoparticles while the shell is made of amorphous nitrogen-doped carbon. With the synergy of multi-phase nanocores, the confining effect of the carbon shell and the in -depth nanocrystallization of Sn/FeSn 2 /FeO nanocores in the yolk-shell nanostructures, Sn/FeSn 2 /FeO@C nanocomposites exhibit high capacity of 601 mAh g−1 at 0.1 Ag−1 after the 300th cycle and capacity of 484 mAh g−1 at 0.5 Ag−1 after the 600th cycle. Our work suggests that high-performance battery materials can be produced by rational structure engineering of multi-phase nanocomposites. [ABSTRACT FROM AUTHOR]

In this study, Mo elements (0.5 wt %, 1.0 wt %, and 1.5 wt %) were doped by the powder metallurgic method to improve the abrasion resistance of in-situ Cr 3 C 2 -20 wt % Ni composites. The dry sliding friction experiments against Al 2 O 3 ceramic were systematically investigated under different loads (25 N, 50 N, 75 N, and 100 N) at room temperature. Experimental results indicated that the hardness, bending strength, and fracture toughness of Cr 3 C 2 -20 wt % Ni composites increased with an increase in the Mo content due to the grain refinement and solution strengthening. The coefficient of friction and wear rate of theses composites risen with an increase in the load, thus changing the wear mechanism from abrasive wear and partial oxidation wear to serious fatigue wear. The tribological behaviors of in-situ Cr 3 C 2 -20 wt % Ni composites were obviously improved by doping Mo, which accomplished by the superior mechanical properties of Cr 7 C 3 phases and the formation of lubricated MoO 3. • In-situ Cr 3 C 2 –Ni composites were prepared by doping Mo element. • Mechanical properties of Cr 3 C 2 –Ni composites risen with Mo content increasing. • Tribological behaviours of Cr 3 C 2 –Ni composites were improved by doping Mo. [ABSTRACT FROM AUTHOR]