In this paper, heterogeneous L12 particles were successfully introduced into Ni38Co25Fe13Cr10Al7Ti7 MPEA by two-stage aging treatment. Compared with the homogeneous particles, the heterogeneous L12 particles strengthened alloy exhibits enhanced strength-plasticity synergy. The tensile elongation is 23.2%, which is higher than all samples with the homogeneous particles, and the yield strength remains at 942 MPa, which is equivalent to the micro particles (972 MPa) with the highest yield strength in the homogeneous particles. Further analysis of the strengthening and deformation mechanisms revealed that precipitation hardening, and heterogeneous deformation-induced hardening were the main factors for the enhanced strength. The deformation-induced layered fracture networks, high-density Lomo-Cottrell locks, and heterogeneous L12 particles microstructure characteristics significantly improve the strain hardening ability; GNDs accumulate at the heterogeneous interface to alleviate the stress concentration at the GBs and improve the tensile plasticity of the MPEA with heterogeneous L12 particle structure. The heterogeneous L12 particle structure obtained through two-stage aging treatment without severe mechanical deformation has attractive engineering application potential. These properties of Ni38Co25Fe13Cr10Al7Ti7 MPEA with heterogeneous L12 particle structure have important enlightening and practical value.

Solving the intermediate-temperature brittleness (ITB) of traditional superalloys and multi-principal element alloys (MPEAs) is a serious challenge. In this paper, a novel MPEA with superior mechanical performance is prepared and successfully overcomes the ITB by simple heat treatment. The effects of different solution treatments on the microstructure and mechanical properties of the alloy are studied. This work shows that the dendrite structure with trimodal gamma' structure is preserved by the subsolvus heat treatment. The heterogeneously distributed trimodal gamma' structure with high volume fraction primary gamma' phases in the interdendritic region effectively prevents the localized slip and enhances the pinning effect of grain boundaries, which inhibits the generation of ITB. The yield strengths of the MPEA with trimodal gamma' structure are 802 +/- 17 MPa at 973 K, 814 +/- 20.7 MPa at 1023 K and 776 +/- 9 MPa at 1073 K, respectively, which are superior than that of most cast superalloys and MPEAs. Moreover, the elongations of the MPEA at 973 K, 1023 K and 1073 K are 10.6 +/- 1.3 %, 14.2 +/- 1.4 % and 11.0 +/- 1.5 %, respectively, which increase by 214.9 %, 510 % and 219.4 %, respectively, compared with the MPEA with uniformly distributed bimodal gamma' structure. Meanwhile, the MPEA shows the best intermediate temperature plasticity (14.2 +/- 1.4 %) at 1023 K due to the microstwinning. The scheme of combining MPEAs with the trimodal gamma' structure and microtwinning opens up a new avenue for the development and manufacture of advanced high-temperature structural materials.

In this paper, heterogeneous L1 2 particles were successfully introduced into Ni 38 Co 25 Fe 13 Cr 10 Al 7 Ti 7 MPEA by two -stage aging treatment. Compared with the homogeneous particles, the heterogeneous L1 2 particles strengthened alloy exhibits enhanced strength -plasticity synergy. The tensile elongation is 23.2%, which is higher than all samples with the homogeneous particles, and the yield strength remains at 942 MPa, which is equivalent to the micro particles (972 MPa) with the highest yield strength in the homogeneous particles. Further analysis of the strengthening and deformation mechanisms revealed that precipitation hardening, and heterogeneous deformation -induced hardening were the main factors for the enhanced strength. The deformationinduced layered fracture networks, high -density Lomo-Cottrell locks, and heterogeneous L1 2 particles microstructure characteristics significantly improve the strain hardening ability; GNDs accumulate at the heterogeneous interface to alleviate the stress concentration at the GBs and improve the tensile plasticity of the MPEA with heterogeneous L1 2 particle structure. The heterogeneous L1 2 particle structure obtained through two -stage aging treatment without severe mechanical deformation has attractive engineering application potential. These properties of Ni 38 Co 25 Fe 13 Cr 10 Al 7 Ti 7 MPEA with heterogeneous L1 2 particle structure have important enlightening and practical value.

The 3D printed ceramic body often shrinks considerably after thermal processing, which seriously affects the quality of the final formed parts. In this report, the Al 2 O 3 -Cr composite was manufactured by 3D direct ink writing. After sintering, the final formed parts have no shrinkage and expanded slightly compared with the green body. Cr plays an important role in this process. The oxidation of Cr causes volume expansion to make up for the sintering shrinkage of the ceramic matrix. The Al 2 O 3 -Cr cermet ink exhibits shear-thinning and viscoelastic inversion characteristics, indicating suitability for direct ink writing. A series of printed compacts with different metal and ceramic ratios were sintered at 1600 °C. The related mechanical properties parts and microstructure of Al 2 O 3 -Cr cermets parts generated by 3D direct ink writing were investigated. The data of XPS and SEM indicate that Cr reacts with oxygen in the system to produce Cr 2 O 3 during sintering, which results in the volume expansion of the sintered part. This new method provides a good strategy for controlling and eliminating the shrinkage of cermet parts during sintering.

As an effective technique for fabricating conductive and thermally conductive polymer composites, a multi-filler system incorporates different types and sizes of multiple fillers to form interconnected networks with improved electrical, thermal, and processing properties. In this study, DIW forming of bifunctional composites was achieved by controlling the temperature of the printing platform. The study was based on enhancing the thermal and electrical transport properties of hybrid ternary polymer nanocomposites with multi-walled carbon nanotubes (MWCNTs) and graphene nanoplates (GNPs). With thermoplastic polyurethane (TPU) used as the matrix, the addition of MWCNTs, GNPs and both mixtures further improved the thermal conductivity of the elastomers. By adjusting the weight fraction of the functional fillers (MWCNTs and GNPs), the thermal and electrical properties were gradually explored. Here, the thermal conductivity of the polymer composites increased nearly sevenfold (from 0.36 W·m−1·k−1 to 2.87 W·m−1·k−1) and the electrical conductivity increased up to 5.49 × 10−2 S·m−1. It is expected to be used in the field of electronic packaging and environmental thermal dissipation, especially for modern electronic industrial equipment.

Functionally graded materials (FGMs) are the important content and basis of modern materials research. FGMs films are widely used in many high-tech applications, such as aerospace, bioengineering and nuclear industries, because of their designability, which makes the material have better mechanical properties, heat resistance and other functions. In FGMs film, the simple and fast preparation methods are very necessary, especially for metal-ceramic-based systems. To address the above, high-throughput Ti-Al2O3 FGMs films were synthesized creatively by a magnetron sputtering. The microstructure and elemental composition of Ti-Al2O3 were analyzed to indicate that the shape and size of the particles on the surface of the FGMs films changed. According to the nanoindentation analysis, the results reveal a relationship between graded morphology, indentation depth, hardness, and modulus values. Our work provides a rapid way to study and design novel functionally graded materials.

Due to aerogel ' s network structure, specific surface area, and high porosity, SiO2 aerogel has excellent thermal insulation and inferior mechanical properties. It is challenging to produce micro-objects and complex-shaped objects accurately by traditional manufacturing method because of the fragile mechanical properties. Here, we use 3D printing to fabricate SiO2 aerogels. At the same time, we add opacifiers to reduce the aerogel ' s medium-high temperature thermal conductivity. The thermal conductivity of the SiO2 aerogel printed in the experiment is as low as 0.028 W/(m center dot K) at room temperature. The aerogel doped with 10 wt% SiC has the best thermal insulation at medium-high temperatures. And the 3D printed aerogel doped with 10 wt% SiC has a compression performance of 1.19 MPa, which is more than 10 times better than the usual aerogel. This paper provides a method for creating micro-objects and complex-shaped objects with excellent medium-high tem-perature thermal insulation using Direct Ink Writing (DIW).