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The cast-rolling composite method was used to create a Cu/Al layered composites with thickness of 5 mm. The organizational structure, and strain distribution of the composites, were characterized using SEM, TEM, and EBSD. The mechanical characteristics of the composites was determined, and the evolution pattern of the interface under different strains were observed, the microstructures and tensile deformation behaviors of the test material was analyzed. The results show that the microstructure of the test material showed a multilevel layered structure, and at the interface, an Al2Cu + Al4Cu9intermetallic compounds (IMCs) with a thickness of 380 nm produced. The Al layer's grain size displays a gradient distribution at the micron scale. There are certain differences in Al grain morphology and strain distribution between the rolling direction (RD) and transverse direction (TD). And there are large differences in the grain orientation of the Al grains along the normal direction (ND). There are some twins in the Cu layer, and the grains have no obvious preferential orientation. Cu/Al composites have a higher plasticity than pure Cu and pure Al. In the process of tensile fracture, the cracks are first initiated in the interface layer, but did not expand directly in the longitudinal direction, and after the interfacial restraining effect reached the limit, expansion of cracks into the Cu and Al layers and eventual fracture of the test material. The toughening mechanism of the test material was also analyzed.

The effects of supercritical carbon dioxide (SCCO2) extraction on coal composition, coal rank, pore structure, and combustion reactivity of three typical Chinese low-rank coals (LRCs) were investigated in this study. The results show that the SCCO2extraction process has significantly reduced the moisture content and increased the fixed carbon content of LRCs. The oxygen/carbon atomic ratio of upgraded LRCs decreases, indicating that the coal rank of upgraded LRCs improves after SCCO2extraction, which is consistent to the findings from Fourier transform infrared spectroscopy. The specific surface area and total pore volume of upgraded Hu Lun Bei Er (HLBE) and Zhao Tong (ZT) lignite increase significantly with extraction time and temperature. Thermogravimetric analysis shows that the combustion process of upgraded LRCs is moving toward the high-temperature region and its burnout temperature (Tb) increases. The average reactivity rate (kmean), maximum reactivity rate (kmax), and comprehensive reactivity parameter (S) increase obviously for upgraded HLBE and ZT lignite, whereas they decrease slightly for upgraded Xin Jiang sub-bituminous coal, indicating that the combustion reactivity of upgraded lignite is enhanced by the SCCO2extraction process.

The phase structure in the interface zone of Cu-Al composite plate was studied by EBSD after casting and rolling and different heat treatment temperatures. The grain sizes of the matrix and intermetallic compounds in the interface zone were analyzed statistically. The spatial distribution characteristics of the transverse, rolled, normal and various phases were characterized by inverse pole diagram.The results show that with the increase of heat treatment temperature, the phase of the interfacial area of the composite plate is rearranged, the residual stress can be released, and the zero resolution decreases.The interface zone of cast-rolled Cu-Al composite plate is composed of a layer of intermetallic compound, which is Al2Cu;Two layers of intermetallic compounds, both Al, were formed in the interfacial area after heat treatment at 300°C and 400°C Al2Cu and Al4Cu9;After heat treatment at 450°C, the interface region is composed of three layers of intermetallic compounds, which is Al2Cu, AlCu, Al4Cu9;The grain size of copper matrix is obviously larger than that of aluminum matrix.Matrix aluminum, matrix copper, Al2Cu.The average grains of Cu are mostly large Angle grain boundaries, and the orientation difference of adjacent grains in aluminum layer is much smaller than that in copper layer. After heat treatment at 300°C for 1 hour, the recrystallization degree of the interface zone of Cu-Al composite plate is low.After heat treatment at 400°C for 1 hour, the recrystallization in the interfacial zone of Cu-Al composite plate is not complete;After annealing at 450°C for 1 h, the subgrain boundaries in the aluminum layer grow up, and LAGB is basically converted to HAGB.The distribution characteristics of the characteristic appearance direction in the crystal space of each phase were characterized under the conditions of casting and rolling and different heat treatment temperatures.At the same time, the research results provide theoretical basis and scientific title for optimizing the preparation process and high-end application of Cu-Al composite plate.