Regulating the interfacial reaction of Sc2W3O12/AgCuTi composite filler by introducing a carbon barrier layer

Lightweight aluminum matrix composites with excellent mechanical and thermal properties are urgently required in applications of aerospace, electronics and military industries owning dimensional stability and long-life span. Antiperovskite manganese nitrides can be regarded as ideal reinforcements due to their high mechanical properties, low negative thermal expansion and wide temperature ranges. In this paper, 30 vol % Mn3.1Zn0.5Sn0.4N/Al composites with Mn3.1Zn0.5Sn0.4N particle sizes of 130, 63 and 12 μm were fabricated by vacuum hot-pressing sintering under sintering temperatures of 450, 500 and 550 °C, respectively. Material phase analysis, microstructural characterization, and bulk density measurements of Mn3.1Zn0.5Sn0.4N/Al composites are conducted. Three-point bending and nano-indentation mechanical properties of Mn3.1Zn0.5Sn0.4N/Al composites are studied, while thermal expansion and conductivity of Mn3.1Zn0.5Sn0.4N/Al composites are also investigated. For the Mn3.1Zn0.5Sn0.4N/Al composite sintered at 450 °C with particle size of 130 μm, the Young's modulus of 87.35 GPa, flexural strength of 169.3 ± 7.60 MPa and flexural strain of 3.62 ± 0.09% are produced. Meanwhile, the lowest coefficient of thermal expansion of 3.14 ppm °C−1 and largest thermal conductivity of 126.2 ± 7.0 W m−1 K−1 are possessed as well. Semi-coherent and coherent interfaces of Al–Mn and Sn–Mn3.1Zn0.5Sn0.4N with a width of ~100 nm are determined, which clearly indicates the interfacial characteristics within the Mn3.1Zn0.5Sn0.4N/Al interfacial micro-zones. This work can provide a good understanding and guide for designing and preparing novel structural-functional composite materials with excellent mechanical and thermal properties.

Fabrication, mechanical and thermal behaviors of antiperovskite manganese nitride Mn3.1Zn0.5Sn0.4N reinforced aluminum matrix composites

Reflection high-energy electron diffraction (RHEED) operated at high pressure has been used to monitor the initial growth of titanium nitride (TiN) thin films on single-crystal (100) MgO substrates by pulsed laser deposition (PLD). This is the first RHEED study where the growth of TiN films is produced by PLD directly from a TiN target. At the initial stage of the growth (average thickness ∼2.4 nm) the formation of islands is observed. During the continuous growth the islands merge into a smooth surface as indicated by the RHEED, atomic force microscopy and field emission scanning electron microscopy. These observations are in good agreement with the three-dimensional Volmer–Weber growth type, by which three-dimensional crystallites are formed and later cause a continuous surface roughening. This leads to an exponential decrease in the intensity of the specular spot in the RHEED pattern as well.

Growth of thin films of TiN on MgO(100) monitored by high pressure RHEED

Multifunctional nanostructured NiTi alloy with Invar, Elinvar and Rinvar properties

Materials having good comprehensive performances, such as zero thermal expansion (ZTE), high thermal conductivity, and machinability are in great demand for electronics, precision instruments, and aerospace applications. However, the challenge is that very few materials meet such requirements. In this study, a multicomponent reinforcement with negative thermal expansion (NTE) is designed for metal matrix composites (MMCs) to achieve wide-temperature-range ZTE, high thermal conductivity, and certain machinability. Taking advantage of the giant NTE in La(Fe,Co,Si)13 system, its originally narrow NTE temperature range can be broadened in the multicomponent material (xLFCS). When xLFCS is used as a reinforcement in MMCs and combined with copper, the thermal expansion coefficient of the xLFCS/39.7 vol%Cu composite can be adjusted to nearly zero (−0.2 × 10−6 K−1) over a wide temperature range of 200–320 K. The thermal conductivity of this composite is 44.1 W m−1 K−1, which is about seven times that of LFCS itself. In addition, compared with other ZTE metal-based materials, the present composite has good machinability. This work reports a metal matrix composite with high thermophysical properties and proposes an easy-to-operate method for broadening the temperature range of NTE or ZTE. 

Jin Cui

Papers

Design of negative/nearly zero thermal expansion behavior over a wide temperature range by multi-phase composite

Enhanced thermal stability of Mo film with low infrared emissivity by a TiN barrier layer

Negative thermal expansion, Magnetic and Electronic transport properties in antiperovskite compounds Mn3Ga1-xAgxN (0≤x≤1.0)

Discovery of negative thermal expansion with giant thermal hysteresis in Fe3NiBx