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Chemical composition of 3D printed MCM MATERIAL Chemical composition [%] Fe Ni Cr O Nb C Al Tl Ti MCM 37,7 27,7 12,4 7,4 5,3 2,8 2,4 2,2 2,5 SEM analysis of the 3D printed MCM material provides detailed images of the microstructure (grain size and shape), highlights the quality of the bond at the interface between the metal matrix and the reinforcing particles, including any defects or voids, and is shown in figure 4.
In order to determine the optimal welding parameters and their influence on the quality of the obtained welds, a number of 4 samples from the 3D printed MCM were tested, following the variation of the following parameters: - welding time; - welding energy; - frequency of ultrasound; - ultrasound amplitude; -pressing force or pressure.
The 3D printing manufacturing process generates a heterogeneous microstructure with variations in grain size and distribution leading to non-uniform welding behavior.

While welding the alloy of Al-Mg-Li system (alloy 1424), after quenching and quenching with ageing we can see the decrease in the number of dark and light gray aggregates, however, it is still enough to define the fir-tree structure grains clearly.
Effect of two-step aging on recrystallised grain size of Al–Mg–Li alloy, Materials Science and Technology. 27 (2011) 125-131

Such influences promote the formation of a fine-grained structure and increase the mechanical and operational properties of castings without the addition of special modifying additives.
The change in external conditions, for example, temperature, leads to a change in the structure of the short-range order (interatomic distances, coordination numbers, the geometry of the disposed atoms, and the sizes of the ordered cluster complexes).
The resulting excess of nuclei of crystallization determines the formation of an extremely non-dendritic structure with a grain size approximately equal to the size of the dendritic parameter.

A number of fabric layers circular in shape, were stacked together.
Etching with 40% HF solution for 22 h delineated grain boundaries.
The deep cavities indicate the spalling of smaller grains.

Under the action of the applied load the high manganese austenitic TWIP steel will produce a large number of mechanical twins, and these twins boundaries are acting as strong barriers to subsequent dislocation motion, which significantly improve the hardening rate of materials, delay the necking, and result in the high ductility of high manganese austenitic TWIP steel[3].
It can be seen that the microstructure is austenite, the grains are fine and annealing twins existed, the average grain size is about 60μm.

However, only a limited number of investigations concern the direct heating of steels for the phase transformation, therefore, receive a superficial layer of the appropriate thickness, free of cracks and with high hardness.
The high energy density plasma arc could create a high cooling speed of the hardened layer at the surface just like laser, thus leading to the formation of superfine grains [12].
Martensite formed in the surface hardened layer has the properties of high hardness, fine grain size inherited from the substrate and severe dislocation.

A high number of precipitates can be clearly seen on grain boundaries in the extruded state (Fig 1a).
In Fig. 1b it is observed that the heat treatment produces a fine precipitation inside the grains.

Heat Capacity and Efficiency Experiment of Grinding Fluid During grinding processing of structural ceramics, due to the poor heat conductivity of ceramics material and perfect heat conductivity of diamond grinding material, most of grinding heat transfers through diamond grinding grains to cause the temperature of the grinding grain point to rise in large scale, which could lead the graphitization of diamond grinding material and speed up the wearing of grinding wheel due to the forms such as abnormal dropping caused by softening of resin bond, therefore, cooling capacity is one of important parameters for specialized grinding fluid of ceramics, which can directly influence the heat transfer rate conducting to the work piece and grinding wheel.
From the diagram, we can see that a new infrared absorption peak appears at the point of wave number of 969.9cm -1 after oleyl alcohol spreads on ceramics, which shows that the infiltration of oleyl alcohol on the surface of silicon nitride ceramics will create a powerful adsorption which can made by chemical reaction or formed hydrogen bonding which is half chemical adsorption.

Viewing from the existing literatures [1]-[4], with the join of the pulsed electric current, it can significantly refine the grain structure and improve the macroscopic property of materials.
With its roles of purifying the molten steel, refining the grain, reducing the composition segregation and micro-alloying and etc., it can improve the quality of steel products[5-7].
However, as for the 2# sample of adding 4V pulsed electric field (Figure 7-b), the number and size of inclusions have declined, and main inclusions include metal sulfides with diameter about 10um.

During the developing process, some CsCl dissolve in the water on CsCl film, forming small grains.
As time goes on, the adjacent smaller grains assemble together to form larger ones following the principle of lowest surface energy[12].
Acknowledgments This work is supported by the National Science Foundation of China with contract number of 50972144.