Effect of temperature and stress on high temperature creep behavior of Ni3Al-based single crystal superalloy

The creep behavior and dislocations mechanism of the Ni₃Al-based single crystal alloy IC6SX with [001] orientation were investigated under the testing conditions of 1100 ?°C/137 ?MPa, 1100 ?°C/120 ?MPa and 1070 ?°C/137 ?MPa. It was observed that the temperature and stress had a significant effect on the high temperature creep life of the single crystal alloy. As the temperature was reduced from 1100 ?°C to 1070 ?°C, the creep life increased from 65.07 ?h to 313.8 ?h. As the stress was reduced to 120 ?MPa, the creep life increased to 243.3 ?h. Under the high temperature and low stress condition the dislocations entered the γ′ phase by climbing caused by the atomic diffusion, instead of slipping.     

Characteristic investigation of trilayered Cu/Al8011/Al1060 composite: Interface morphology,microstructure, and in-situ tensile deformation

In this work, Cu/Al8011/Al1060 trilayered composite with an ultrathin copper layer was fabricated successfully by the hybrid process of cast-rolling and hot-roll-bonding. The effects of heat treatment were investigated on the microstructure and mechanical behavior of the composite. The results showed that annealing temperatures above 300°C led to the formation of new intermetallic compounds that joined their initial counterparts. Also, the interface growth was fast above 340°C. It was found that...     

钛含量对电解低钛ZL108合金组织的影响

用已原位钛合金化的电解低钛铝基合金熔配了内燃机活塞常用的不同钛含量(ωTi=O—O.23％)的ZL108合金，进行了合金的成分分析和组织观察，结果表明：随着钛含量的增加，一次和二次枝晶发生了由比较粗大一细小一组大的变化，一次枝晶长度变化不大，二次枝晶发生了由长变短的变化；同时。二次枝晶臂间距和共晶硅颗粒的直径也发生了由大到小而后又增大的变化，在ωTi=O．11％，最小值分别为16．7μm和2．7μm。在ωTi=O．11％-O．16％之间存在着最佳的钛含量，为进一步研究该合金的性能以及工业化生产优质高件能的活塞材料根供了理论和实验依据．     

Zr-xNb-4Sn alloys with low Young’s modulus and magnetic susceptibility for biomedical implants

The microstructure, mechanical and magnetic properties of Zr–x (8, 9, 10, wt.%)Nb–4Sn alloys were investigated to obtain novel Zr-based alloy with low Young’s modulus and magnetic susceptibility for biomedical implants. After homogenization annealing, hot forging and solution annealing, Zr–8Nb–4Sn, Zr–9Nb–4Sn and Zr–10Nb–4Sn alloys were composed of β+α″ phase, β+α″ phase, β+ω phase, respectively. The temperature at which the α" and ω phase were transformed into β phase during the heating process was about 200 ​°C, and the phase transformation temperature decreased with the increase of Nb element. Among all the Zr–x (x ​= ​8,9,10)Nb–4Sn(wt.%) alloys, Zr–9Nb–4Sn alloy had the lowest Young's modulus of 46.6 ​GPa and the low magnetic susceptibility of 1.294 ​× ​10⁻⁶ cm³g⁻¹, which has a good application prospect for biomedical applications.     

Computational diffusion kinetics and its applications in study and design of rare metallic materials

Computational diffusion kinetics(CDK),with a spirit of and being coupled with the computational thermodynamics(CT,or called as the CALPHAD technique),plays increasingly important role in the alloy design/optimization and microstructure control during the processing of advanced metallic materials.This paper is to highlight recent progress of CDK in research with great focus on novel Ti and Zr alloys,which was largely performed in the authors’group.It ends with one representative example of the applications of CDK,coupled with CT,quantitative phase field,and three-dimensional(3D)statistical calculation,in designing the heattreatment schedule for the dual phase(αβ)Ti–6Al–4V alloys.     

凝胶注模成型Yb:YAG透明陶瓷的微观结构和光学性能的研究

以共沉淀法制备的Yb:YAG粉体为原料,采用凝胶注模成型方法和真空烧结技术制备出了Yb:YAG透明陶瓷.通过扫描电子显微镜(SEM)对素坯和陶瓷的微观形貌进行了表征.结果表明,凝胶注模成型工艺所得的素坯致密度高,均匀性好;陶瓷晶粒排列紧密,晶界清晰无杂相,平均晶粒尺寸约为20nm.得到的透明陶瓷样品光学质量较好,在1064nm处直线透过率达到77%.表明凝胶注模成型是一种用来制备Yb:YAG透明陶瓷的有效的成型方法.     

Effect of initial orientation on microstructure and mechanical properties of AZ31 Mg alloy sheets via accumulated extrusion bonding

In this study, effects of initial orientation on microstructure evolution and mechanical properties of AZ31 Mg alloy sheets via accumulated extrusion bonding(AEB) was systematically studied. The samples with RD and TD parallel to extrusion direction(ED) were labeled as RED and TED, respectively. RD and TD pieces alternately stacked was named as RTED. The results revealed that under three-dimensional compressive stress, {10-12} tensile twinning dominated the first stage deformation in container. ...     

Na3Sc2V3O12∶Fe3 ＋掺杂体系微观结构的理论研究

基于三角对称下3d5组态体系的完全能量矩阵,通过理论模拟实验的EPR参量,运用2个不同的参数值A4（这2个参数分别来自赤铁矿和钇铁石榴石的光谱）,研究了Na3Sc2V3O12石榴石晶体中的四面体三价铁中心的光谱和局域微观结构。计算结果与已有的实验值相吻合。     

Biomimetic preparation and multi-sc ale microstructures of nano-sil ica/polyurethane elastomeric fibers

Bioinspired by the spinning of spider silks,the biomimetic preparation of nano-silica/polyurethane（nano-SiO/TPU） elastomeric fibers with distinctive multi-scale microstructures was successfully implemented.The formation mechanism of the nano-SiO₂/TPU fibers was considered as the integrated mechanism of diffusion,coagulation,self-assembly,and microphase separation,same as that of the native spider silks.The mass ratio of nano-SiO₂ to TPU greatly influenced the external and inner microstructures of the nano-SiO₂ATPU fibers.The formation process of the nano-SiO₂/TPU fibers was simply described as three main stages,and the second stage,such as the adding of the ethanol solvents and nano-SiO₂ in different diameters,was thought to be very crucial for the final external and inner microstructures of the prepared fibers.For example,the adding of the ethanol and the nano-SiO₂ spheres in diameter of 10 nm resulted in the existence of many TPU-self-assembled microspheres mostly spaced apart by the nano-SiO₂ aggregates in the nano-SiOVTPU fibers,while the adding of the ethanol and the nano-SiO₂ spheres in diameter of 100 nm resulted in the existence of the nano-SiO₂ spheres,instead of the TPU-self-assembled microspheres,distributed in the nano-SiO₂/TPU fibers.