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Residual stress runs through the whole life cycle of materials and components，including design， production， processing， manufacturing， service and failure， and is a key factor affecting the processing accuracy， dimensional stability and fatigue strength of materials and components. It is important to know how to accurately and non-destructively characterize residual stresses. Compared with the traditional laboratory X-ray diffraction method， synchrotron X-ray diffraction has significant advantages in brightness， collimation， time resolution， spatial resolution， penetration depth， etc. It is one of the most effective methods for non-destructive in-situ accurate characterization of residual stresses in engineering materials and key components. This paper focused on the research progress of synchrotron radiation X-ray diffraction technology in material residual stress， highlighting the analysis of residual stress in high temperature alloys during the additive manufacturing process， the effect of laser shot peening-technology on residual stress in titanium alloys， the evaluation of residual stress in welded aluminum alloys， the influence of heat treatment parameters on residual stress in structural steels， and the study of residual stress in ceramic coatings. Finally， the shortcomings of synchrotron X-ray diffraction technology in industrial applications are analyzed， and the future research and development directions are prospected， including the development of in-situ test environment and devices， and the combination of synchrotron radiation X-ray diffraction technology and other non-destructive testing methods.

Scanning electron microscopy, transmission electron microscopy and energy disperse spectrum were used to analyze the morphologies, microstructures and compositions of Hf-rich inclusions in DZ125 and DZ22 Ni-based superalloys. The solidification microstructures of Ni-based alloys with different Hf additions were investigated by simulation experiments, and the formation mechanism of Hf inclusions was clarified. The results indicate that there are irregular inclusions on the edges of DZ125 and DZ22 alloys. The white inclusions are HfO2 phase, and the accompanying gray inclusions mainly comprise Al2O3. The Hf has a strong tendency to accumulate in the alloy, and large size Hf-rich phase of above 100 μm can form in the alloy when the Hf content is high. With the decrease of Hf content, the Hf-rich phases become smaller and distributed more evenly. At high temperature, Hf has a high strong driving force of spontaneous reaction with oxygen in the alloy melt and ceramic shell/core oxides, leading to the formation of HfO2 inclusions on the casting surface. When the dispersion of Hf is insufficient, Hf tends to segregate at the interface of oxide ceramic phases and melt, reacting with Al2O3 in the ceramic and SiO2 in the silica sol binder at high temperature, resulting in the formation of HfO2 inclusions on the casting surface.

Polyurethane is a coating material widely used in the field of anti-corrosion and wear resistance. At present, a lot of research work has been carried out in the research and development of polyurethane materials and process improvement. However, there are few researches on the characterization methods of polyurethane coatings, and suitable characterization methods are selected. Conducive to the improvement and application of materials. This article summarizes the characterization methods of polyurethane coatings from the aspects of morphology, structure, mechanical properties, electrochemical properties and thermodynamic properties. It is found that there is no standardized and unified evaluation standard for the electrochemical characterization methods of polyurethane; polyurethane as a high molecular polymer has a certain sensitivity to the service environment. Humidity and temperature have a great influence on its physical and chemical properties. Conventional characterization methods cannot perform microstructure characterization under the stress state of the material and the service environment. The establishment of standardized and unified electrochemical evaluation standards for polyurethane; the ability to characterize polyurethane under service conditions is an important research direction for improving the characterization method.

HIPed FGH96 superalloy prepared by AA powder was used as the research object, and the PPB precipitations and microstructures before and after different hot deformations were studied. The results show that PPB precipitates with circular distribution can be seen in HIPed FGH96 superalloy, and the coarse strip prime γ′ phase with circular chain distribution is one of the main characters of PPB. After hot deformation, the PPB in FGH96 superalloy is deformed and broken, the recrystallization grains are refined and twisted, and the grain misorientation becomes smaller. With the increase of deformation temperature and hot deformation, and the decrease of deformation rate, the deformation and fragmentation of PPB precipitates are more significant, the size of the primary residual γ′ phase becomes smaller, and the volume becomes less. The increase of deformation temperature and hot deformation, and the decrease of deformation rate are beneficial to reduce or even eliminate PPB precipitations.

The influence of different grades of prior particle boundary (PPB) in PM FGH96 superalloy during high-cycle fatigue test at 550 ℃ was investigated by the in-situ fatigue test in SEM. The results show that the PPB in P/M FGH96 superalloys by plasma rotating electrode process (PREP) + hot isostatic press (HIP) is constituted of large size γ' and carbide. There are no significant effect on the initiation and propagation of high cycle fatigue crack in different grades of PPB. Crack initiation is initiated in the grain interior, and the propagation is transgranular or intergranular, which is influenced by the angle between the grain boundary and the stress axis. In the fast crack growth zone and the transient zone, the fracture characteristics of serious grade PPB FGH96 superalloy are transgranular and along PPB globular surfaces.

In this research, Ti-15V-3Cr-3Al-3Sn alloy ingots were prepared using ceramic mold and centrifugal casting. The Ti-15V-3Cr-3Al-3Sn setting casting, for aeronautic engine, with 1.5 mm in thickness was manufactured. The alloy melting process, precision casting process, and problems in casting application were discussed. Effects of Hot Isostatic Pressing and heat treatment on the mechanical properties and microstructure of the Ti-15V-3Cr-3Al-3Sn alloy were studied.

This study is a preliminary investigation exploring the mechanical properties of three‐dimensional (3D)‐printed personalized mesh titanium alloy prostheses and the feasibility of repairing hemi‐mandibular defects. The ANSYS 14.0 software and selective laser melting (SLM) were used to produce personalized mesh titanium alloy scaffolds. Scaffolds printed using different parameters underwent fatigue property tests and scanning electron microscopy (SEM) of the fracture points. Models of hemi‐mandibular defects (encompassing the temporomandibular joint) were created using beagle dogs. Freeze–dried allogeneic mandibles or 3D‐printed personalized mesh titanium alloy prostheses were used for repair. Gross observation, computed tomography (CT), SEM, and histological examinations were used to compare the two repair methods. The prostheses with filament diameters of 0.5 and 0.7 mm could withstand 14,000 times and >600,000 cycles of alternating stresses, respectively. The truss‐structure scaffold with a large aperture and large aperture ratio could withstand roughly 250,000 cycles of alternating forces. The allogeneic mandible graft required intraoperative shaping, while the 3D‐printed mesh titanium alloy prostheses were personalized and did not require intraoperative shaping. The articular disc on the non‐operated sides experienced degenerative changes. No liver and kidney toxicity was observed in the two groups of animals. The 3D‐printed mesh titanium alloy prostheses could effectively restore the shape of the mandibular defect region and reconstruct the temporomandibular joint. [ABSTRACT FROM AUTHOR]

Two kinds of indium-based MOF materials (In-MOF 1 and In-MOF 2) were synthesized using a solvothermal method using two different pyridine carboxylic acid ligands. Single crystal X-ray diffraction shows that In-MOF 1 is a three-dimensional frame containing four connected [In(CO2)4] units and nine connected [In3(μ3-O)(CO2)6N3] units, while In-MOF 2 is a three-dimensional structure with eight connected [In(CO2)3(CO)N] units. Moreover, the adsorption and separation properties of the MOFs for C2H2, CO2 and CH4 were investigated systematically in order to study the regulation of porosity by the subtle changes in the structure of organic linkers. The results show that both kinds of MOFs have certain gas adsorption and separation capacity, which is mainly determined by the structure, function and adjustable porosity. This work not only reports two MOFs with the potential to separate C2H2/CH4, CO2/CH4 and C2H2/CO2, but also provides valuable guidance for the design and synthesis of porous MOFs with better performance in the future. [ABSTRACT FROM AUTHOR]