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41.
为了提升大断面球墨铸铁综合力学性能,通过复合添加微量合金元素铜、锑、锡、钼对大断面球墨铸铁进行微合金化处理,借助金相显微镜(OM)、扫描电子显微镜(SEM)及力学性能测试等手段,研究了Cu Sb Sn Mo复合微合金化大断面球墨铸铁微观组织和力学性能。结果表明,试验球墨铸铁具有良好的综合力学性能。大断面球墨铸铁中添加铜、锑、锡、钼后优化了材料的组织结构,基体组织为珠光体+少量牛眼状铁素体;试样石墨组织细小、圆整,分布均匀。同时,合金元素的复合加入使得其抗拉强度达到800 MPa以上,硬度约为280HB,伸长率达到5%以上。拉伸断口分析表明,微合金化大断面球墨铸铁断裂模式以解理断裂为主,伴有少量的塑性变形。 相似文献
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In order to improve the process effectiveness and joint quality, ultrasonic vibrations were integrated with friction stir lap welding. Effect of ultrasonic exertion on the process and joint quality of AA 6061-T6 were investigated. Upon ultrasonic exertion, joints owned larger effective lap width, shorter hooks and improved strength. Weld fracture mode changed from a ductile–brittle mixed mode to a more ductile mode while the fracture path shifted from lap interface to beyond the stir zone. Material flow and interface defects were characterised using lap welded dissimilar aluminium alloy joints. Ultrasonic vibration improved the material flow and reduced the interfacial defects. Variations in failure load of joints were found in accordance with the variations in material flow and interfacial defects. 相似文献
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The present study focuses on experimental investigation of through the thickness displacement and strain field in thin adhesive layer in single sided (unsymmetrical) patch repaired CFRP (carbon fiber reinforced polymer) panel under tensile load. Digital image correlation (DIC) technique is employed to acquire the displacement and strain (longitudinal, peel and shear) field. Experimental determination of shear transfer length based on shear strain field obtained from DIC is introduced to estimate the optimum overlap length which is an essential parameter in patch design for the repair of CFRP structures. Further, DIC experiment with magnified optics is performed to get an insight into complex and localized strain field over thin adhesive layer especially at critical zones leading to damage initiation. The failure mechanism, load displacement behavior, damage initiation and propagation are closely monitored using DIC. The influence of patch edge tapering on strain distribution in adhesive layer is also investigated. The DIC successfully captures the global and localized strain field at critical zones over thin adhesive layer and further helps in monitoring the damage based on strain anomalies. Strains are found to have maximum magnitude at the patch overlap edge and the shear strain level in adhesive layer is higher than the peel strain. Normal tapering increases the peel strain and has negligible influence on shear strain level in adhesive layer. The recommended overlap length is found to be consistent with the recommendation in the literature. Whole field strain pattern and the overlap length obtained from experiment are further compared with the finite element analysis results and they appear to be in good coherence. 相似文献
46.
Ponnusamy Nandha Kumar Shangavi Subramanian Uthirapathy Vijayalakshmi Sanjeevi Kannan 《Journal of the American Ceramic Society》2020,103(6):3528-3540
Structurally stable β-Ca3(PO4)2/t-ZrO2 composite mixtures with the aid of Dy3+ stabilizer were accomplished at 1500°C. The precursors comprising Ca2+, P5+, Zr4+, and Dy3+ have been varied to obtain five different combinations. The results revealed the fact that complete phase transformation of calcium-deficient apatite to β-Ca3(PO4)2 occurred only at 1300°C, whereas the evidence of t-ZrO2 crystallization is obvious at 900°C. The dual occupancy of Dy3+ at β-Ca3(PO4)2 and t-ZrO2 structures was evident; however, Dy3+ initially prefers to occupy β-Ca3(PO4)2 lattice until its saturation limit and thereafter accommodates at the lattice site of ZrO2. The typical absorption and emission behavior of Dy3+ were noticed in all the systems and, moreover, the surrounding symmetry of Dy3+ domains has been determined from the luminescence study. All the systems ensured paramagnetic response that is generally contributed by the presence of Dy3+. A gradual increment in the phase content of t-ZrO2 in the composite mixtures ensured a significant improvement in the hardness and Young's modulus of the investigated compositions. 相似文献
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系统地论述了氧气底吹熔炼氧枪的结构、工作原理、设计计算方法、材质及蚀损机理.指出了延长氧枪使用寿命的措施。 相似文献
48.
垦71井区三维VSP资料波场分离方法应用研究 总被引:8,自引:5,他引:3
三维VSP资料是多偏移距VSP资料,资料中多种类型的波叠合在一起形成复杂波场。从复杂波场中分离出单一的保幅反射波波场是三维VSP波场分离的重要工作。常规二维VSP波场处理方法单一,难以适用于复杂的三维波场处理。针对三维VSP资料的波场特点,以分离上行反射P波为例,将单一波场分离方法加以适当组合,对垦71井区三维VSP实际资料进行了应用研究。结果表明,波场分离处理中叠加消去法和中值滤波相结合以及F—K滤波和中值滤波相结合的方法克服了单一方法的缺陷,波场处理后获得了波组特征明显、波场清晰单一的上行反射P波保幅波场,取得了较好的波场分离效果。 相似文献
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