Mingxing Guo

Influence of thermomechanical processing on microstructure, texture evolution and mechanical properties of Al–Mg–Si–Cu alloy sheets

Abstract Influence of thermomechanical processing on the microstructure, texture evolution and mechanical properties of Al–Mg–Si–Cu alloy sheets was studied systematically. The quite weak mechanical properties anisotropy was obtained in the alloy sheet through thermomechanical processing optimizing. The highly elongated microstructure is the main structure for the hot or cold-rolled alloy sheets. H {001}〈110〉 and E {111}〈110〉 are the main texture components in the surface layer of hot-rolled sheet, while β -fibre is dominant in quarter and center layers. Compared with the hot-rolled sheet, the intensities of β -fibre components are higher after the first cold rolling, but H {001}〈110〉 component in the surface layer decreases greatly. Almost no deformation texture can be observed after intermediate annealing. And β -fibre becomes the main texture again after the final cold rolling. With the reduction of the thickness, the through-thickness texture gradients become much weaker. The through-thickness recrystallization texture in the solution treated sample only has cube ND {001}〈310〉 component. The relationship among thermomechanical processing, microstructure, texture and mechanical properties was analyzed.

Effect of rolling geometry on the mechanical properties, microstructure and recrystallization texture of Al-Mg-Si alloys

The effect of rolling geometry on mechanical properties, microstructure, and recrystallization texture of Al-Mg-Si alloys was studied by means of tensile tests, microstructural observations, and electron backscatter diffraction measurements. The results reveal that the elongation and the average plasticity strain ratio (r) values of the T4P (pre-aging plus natural aging)-treated alloy sheet with a rolling geometry value between 1 and 3 are somewhat higher than those of the T4P-treated sheet with a rolling geometry value between 3 and 6. The deformation and recrystallization microstructures of the sheet with a rolling geometry value between 1 and 3 are more uniform than those of the sheet with a rolling geometry value between 3 and 6. The former also possesses somewhat higher surface quality. H {001}〈110〉 and Goss {110}〈001〉 orientations are the main recrystallization texture components for the former case, whereas the latter case only includes H{001}〈110〉 orientation. Texture gradients are present in the two alloy sheets. Shear texture component F on the surface of the sheet with a rolling geometry value between 3 and 6 and its higher texture gradients have revealed that non-uniform deformation occurred during cold rolling. The effects of texture on the yield strength and r value were also discussed.

Relationship among mechanical properties anisotropy, microstructure and texture in AA 6111 alloy sheets

We comparatively studied the mechanical properties anisotropy, microstructure and texture of the commercial and the new developed AA6111 alloys through tensile test, optical microscopy, and XRD analysis. The results show that the anisotropy of mechanical properties for the developed AA6111 alloy is lower than that of the commercial alloy. The developed alloy possesses higher r value, lower Δr value and more uniform microstructure, compared with the commercial AA6111 alloy, indicating that the deep drawability of the developed alloy has been improved significantly. The recrystallization textures of the two alloy sheets are also different. The recrystallization texture of the commercial alloy sheet mainly includes Cube and {114}<311> orientations, while the recrystallization texture of developed alloy sheet consists of Cube, Goss and R orientations. The relationships among the deep drawabilities, microstructure and texture were discussed thereafter.

Effect of particle size distribution on the microstructure, texture, and mechanical properties of Al–Mg–Si–Cu alloy

The effect of particle size distribution on the microstructure, texture, and mechanical properties of Al–Mg–Si–Cu alloy was investigated on the basis of the mechanical properties, microstructure, and texture of the alloy. The results show that the particle size distribution influences the microstructure and the final mechanical properties but only slightly influences the recrystallization texture. After the pre-aging treatment and natural aging treatment (T4P treatment), in contrast to the sheet with a uniform particle size distribution, the sheet with a bimodal particle size distribution of large constituent particles and small dispersoids exhibits higher strength and a somewhat lower plastic strain ratio (r) and strain hardening exponent (n). After solution treatment, the sheet with a bimodal particle size distribution of large constituent particles and small dispersoids possesses a finer and slightly elongated grain structure compared with the sheet with a uniform particle size distribution. Additionally, they possess almost identical weak recrystallization textures, and their textures are dominated by CubeND {001}<310> and P {011}<122> orientations.

Controllable preparation of anatase TiO2 nano arrays on Ti foil for flexible dye-sensitised solar cells

Abstract Flexible dye-sensitised solar cells (DSSCs) have been attracting considerable attention because of its flexibility and lightweight. In this study, TiO2 nano arrays with different morphologies were successfully synthesised on Ti foil via hydrothermal process. The effects of preparing conditions such as concentration of NaOH solution, hydrothermal temperature, reaction time and the additive NaCl on the formation of TiO2 nano arrays were systematically investigated by X-ray diffraction, scanning electron microscopy and photovoltaic tests. The growth mechanisms of nano arrays with different morphologies were also discussed. Moreover, the as-prepared TiO2 nanosheets array film was used as a photoanode of the flexible DSSC, a power conversion efficiency of 1.88% was obtained.

INFLUENCE OF DIFFERENT THERMOMECHANICAL PROCESSES ON THE MECHANICAL PROPERTIES AND MICROSTRUCTURE OF Al-Mg-Si-Cu ALLOY SHEETS

通过拉伸实验，并利用OM，SEM，TEM观察以及EBSD测试手段，研究了不同热加工工艺对Al-Mg-Si-Cu系合金板材力学性能和组织，包括织构的影响规律．结果表明，热加工工艺的变化对T4P预时效态合金的强度和应变硬化指数n基本无影响，但是对平均塑性应变比r^-,平面各向异性度△r以及不同方向延伸率影响显著：热轧之后首先进行一定量的冷轧变形然后再进行退火处理获得的合金板材（工艺II）较热轧后直接进行退火处理（工艺I）获得的合金板材在固溶之后的成形性能要好，r^-可达0．6187，同时各向异性明显减小；虽然工艺I处理的合金板材固溶过程中PSN效应显著，但是工艺II固溶处理前的冷轧变形量和不同尺寸粒子分布情况设计合理，再结晶晶粒基本呈等轴状，且仅含有强度较低的CubeND，Cube和H织构．并根据热加工工艺对合金板材显微组织的影响规律，提出该系合金随热加工工艺进行的组织演化模型示意图．