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The 2195 Al-Cu-Li alloy is widely utilized in the aerospace industry due to its lightweight nature and high strength. Consequently, gaining a comprehensive understanding of techniques to enhance its microstructural and mechanical properties is crucial for the consistent production of reliable and high-strength aerospace components. In this investigation, a pristine 2195 industrial ingot was subject to three distinct forging pretreatments: PT1, which involved a direct three upsetting and three stretching (3U3S) process; PT2, which combined double stage homogenization (DH) with 3U3S; and PT3, which involved DH along with six upsetting and six stretching (6U6S). Subsequent warm deformation and T8 aging treatment were applied to the pretreated forgings. The microstructure evolution during the processes and the final mechanical properties in three orthogonal dimensions were examined. The findings revealed that the combination of DH and multi-dimensional forging (MDF) facilitated the dissolution of non-equilibrium phases to a greater extent. Consequently, the main strengthening phase transformed from the T 1 + δ' phase observed in PT1 to the denser T1 + little θ' phase observed in PT2 and PT3 after T8 aging treatment. Notably, the tensile strength and yield strength of PT2 and PT3 specimens increased by 20–30 MPa in all three directions. Moreover, the MDF process accelerated the recrystallization behavior from PT1 to PT3, resulting in a gradual reduction in the average grain size of the pretreated samples from 356 µm to 186 µm. Following warm forging and T8 aging, the grains exhibited a finer and equiaxed structure. Additionally, the coarse phase was identified as the primary source of transgranular cracking. The coarse phases within the matrix became more homogeneous and finer from PT1 to PT3, with a gradual decrease in their area fraction. On the fracture surfaces, the aggregation of coarse phases diminished. Consequently, the elongation in the z-direction improved, and the elongation anisotropy and standard deviation decreased in all three directions for PT3 specimens. The findings presented in this study provide valuable insights into the high-performance manufacturing of Al-Cu-Li alloys. • The DH and doubling the strain of MDF both promoted the dissolution of non-equilibrium phases. • Combine DH treatment with MDF enhanced the precipitation kinetics of the T 1 phase, increasing the strength by 20–30 MPa. • The coarse phase was the main transgranular cracking sources, which was diminished gradually by the improved process. [ABSTRACT FROM AUTHOR]

As an additive manufacturing technology, Fused Deposition Modeling and Sintering (FDMS) technology can give diamond tools some creative structures to be applied in more fields. To explore the influence of diamond parameters on diamond tools manufactured by FDMS, copper-tin-diamond composite samples with different diamond concentrations and particle size were prepared by FDMS technology in this paper. During the study, the morphological characteristics of diamond particles inside the samples during the debinding and sintering process are summarized and the influence of diamond parameters on the mechanical properties and structure of the samples was further explored. These influence laws were also verified by cutting experiments. The results show that most diamond particles are in an incomplete coating state because of the volatilization of the binder. Meanwhile, a higher concentration of diamond will lead to more pores and cavities in the samples; and the cavities can be connected to form a large area of cavity zone by the print layer, thereby resulting in a serious loss in the performance of the samples. On the other hand, a small diamond particle size can lead to agglomeration of particles. Subsequently, this will result in void generation and regional weakening of the holding ability. However, agglomeration and some pores or cavities will increase the wear of the matrix, expose more diamond particles, and finally improve the cutting efficiency of the dicing blades when cutting sapphire crystal. Excessive wear may reduce the life of the diamond tool, but improved of sharpness can be better applied in the field of precision machining. • Higher concentration of diamond will lead to more pores and cavities. • The cavities will be connected and form a cavity zone due to FDMS process. • Agglomerates can lead to void generation and weakening of the holding ability. • Increased diamond concentration amplifies the effect of particle size on agglomeration. • Appropriate diamond parameters can prevent crack propagation. • Characteristic endowed by FDMS will improve the cutting efficiency of tools. [ABSTRACT FROM AUTHOR]

• Co-based diamond composites were separately fabricated via the FDMS and the powder hot-pressed sintering technology. • There is a certain difference in the overall performance of the two kinds of specimens. • The Co-based samples fabricated by FDMS form a special coating state for diamond particles. • The Co-based samples fabricated by FDMS have defects of high porosity inside the matrix. • The reduction of knife-cut features can represent the improvement of density and holding ability of the FDMS sample. Fused deposition molding and sintering (FDMS) technology has the characteristics of low cost and low damage to diamonds. In order to explore more possibilities of additive manufacturing diamond tools, FDMS technology was considered to manufacture Co-based diamond composites at different temperatures in this paper. Also, specimens of Co-based diamond composites were manufactured under the same sintering process by using the powder hot-pressed sintering technology. And the matrix microstructure and properties of the specimens made by those two different technologies were analyzed and compared. The results show that a lot of porosity defects were developed inside the specimens manufactured by FDMS. This is because of the specific process characteristics of FDMS. Also, the matrix forms a special coating state for diamond particles due to the binder system used in this study, which causes some diamond particles to suffer slight thermal damage. These all will reduce the density and holding ability of the FDMS specimens. However, when the sintering temperature increases from 800 °C to 880 °C, the performance loss of FDMS samples caused by the porosity defects gradually decreases, thereby reducing the performance difference when comparing with the powder hot-pressed sintering specimens. In addition, the matrix structural uniformity of the FDMS specimens is significantly improved during this process, and the fracture feature changes from intergranular fracture to transgranular fracture. But there is still a certain difference in the overall performance of the two kinds of specimens at the optimal sintering temperature. Therefore, the further optimization of FDMS process parameters and binder system is of great significance for the application of FDMS in diamond tools. [ABSTRACT FROM AUTHOR]