Microstructure,mechanical properties and wear resistance of an Al–Mg–Si alloy produced by equal channel angular pressing

Microstructure, mechanical properties and wear resistance in an ultrafine-grained Al–Mg–Si alloy fabricated utilizing a combination of equal channel angular pressing (ECAP) and dynamic aging were investigated in this paper. The results indicated that the grain size of the ECAP alloy was significantly refined, i.e., to ~239 nm after three ECAP passes. Meanwhile, the yield and tensile strength of the ECAPed material reached 340 MPa and 445 MPa, respectively, while maintaining a significant uniform elongation of 14%. Wear resistance results demonstrated that the wear rate, wear depth and width of the ECAPed material decreased in comparison with the solution-treated (SST) and peak-aged (T6) conditions under a load range of 5–25 N. The adhesive wear that occurs in the undeformed specimens at 10 N does not appear in the ECAPed specimen at the same load, indicating that the ECAPed specimen delay the appearance of more serious wear mechanisms under certain loads. The cooperative interaction of high density nano-scale β" precipitates and dislocations resulted in a combination of super-high strength and good work hardening ability which suppressed the extension of cracks between the friction layer and the plastic deformation zone. As a consequence, the combination of ECAP and dynamic aging brings a significant improvement for antifriction performance of the 6061 aluminum alloy.     

Effect of heat treatment on microstructures and properties of a novel Al-Zn-Mg-Cu alloy for oil drilling

In view of the special requirements for strength, heat resistance and corrosion resistance of Al-Zn-Mg-Cu alloy for oil drilling, the Al-6.2 Zn-2.5 Mg-1.6 Cu alloy was prepared by increasing Cu content on basis of Russian Series 1953 alloy. The effect of heat treatment on the microstructures and properties of the alloy was characterized by optical microscope(OM), scanning electron microscope(SEM) and transmission electron microscope(TEM), and investigated by tensile test at room temperature, thermal exposure test and corrosion test. The results show that the strength after T6 aging treatment exhibit a decrease trend as an increase of the solution temperature from465 °C to 480 °C. After the solution treated by the rate of 470 °C/1 h, second phases dissolve into the matrix very well and the strength property reaches optimum. The alloy has better comprehensive properties treated by a solution treatment of 470 °C/1 h and then followed by an aging treatment of 120 °C/24 h + 170 °C/1 h + 120 °C/24 h. Under the aging state, the precipitated phases inside the grains are suitable in size, while on the grain boundary distribute discontinuously and the precipitate-free zone is obvious. Besides, the alloy still maintain high tensile properties. The yield strength, tensile strength and elongation are 650 MPa, 686 MPa,12.0%, respectively. The yield strength retention after heat exposure is 92%. The alloy has good corrosion resistance and the exfoliation corrosion degree. The average corrosion rate in the H_2S and CO_2 environment is 0.0024 mm/a, which is far less than the required 0.12 mm/a. It is insensitive to H_2S and CO_2 environments.     

海上电泵结蜡井热循环洗井工艺参数优化设计

为探索海上油田电泵举升结蜡井热循环洗井工艺井筒温度场分布规律，综合考虑潜油电机增温、电缆散热、热流体注入量、注入深度、注入温度、结蜡管段传热和海水空气导热的影响，基于热能守恒原理，建立了电泵井结蜡热循环洗井工艺井筒温度场计算模型，分析了热流体注入温度和注入量对混合产出流体的井筒温度分布的影响。研究结果表明，随着注入量的增加混合产出液沿程井筒温度增加，随着注入温度的增加混合产出液沿程井筒温度增加。该方法可有效指导现场措施工艺的实施，达到延长结蜡井的清蜡周期、延缓产液/产油量下降速度的目的。     

凋亡抑制蛋白与肿瘤关系的研究

凋亡抑制蛋白(inhibitor of apoptosis proteins,IAPs)可以作为癌症诊断和治疗的靶点,在肿瘤研究方面备受关注,就凋亡抑制蛋白的结构、功能、在肿瘤中的表达与肿瘤的关系等研究进展作一综述,为凋亡抑制蛋白的研究提供信息和思路.     

不良地质条件下管道基础处理与施工

管道输送是一种较为安全的运输手段，但在不同的地质条件下的管道设计与施工有着不同的技术要求。文章介绍了在湿陷性黄土地区基处理的几种方法以及灰土及砂垫层处理方法。     

Pilot Study on Nanofiltration Combined with Ozonation and GAC for Advanced Drinking Water Treatment

IntroductionThe conventional process for surface water treatment,which consists of flocculation, sedimentation and filtrationcurrently, had been applied inproducingdrinkingwater formany years. Although this process can remove turbidityand bacteria in surface water effectively, only about from20% to 30% of natural organic matter ( NOM) can beeliminated. When the purified water is disinfected bychlorination, these NOMs may react with chlorine. As aresult some dis…     

建筑物地基处理的设计与施工探讨

以具体工程为例，介绍了建筑物地基处理的设计、施工中遵循的原则，施工中遇到特殊情况时采取的处理方法和必要的检测方法，对几种桩基的设计要求、施工工艺及过程、质量控制等情况进行了简单阐述。     

给水处理系统高效经济运行的生产性评价

研究给水处理系统的高效经济运行技术 ,是保证水厂高效、安全、经济供水的重要措施 .生产运行实践证明 ,采用高效经济方式运行的确可以节约可变费用 .尤其是在冬季低温低浊水的净化中 ,可变费用的节约程度最高可达 2 0 %以上     

传染病医院污水处理工艺选择案例

文章通过对临汾市传染病医院拟建的传染病区污水的来源、排放量、污染物的分析,结合污水处理原则,提出了具体的污水处理工艺。并根据污染物去除率预测了污染物浓度,与污染物排放标准进行对比分析,结果表明所选工艺处理后的污染物浓度能够达标,污水处理工艺是可行的。     

40Cr大轴断裂分析

对冶金矿山某产品的40Cr材料制作的大轴热处理后发生断裂现象，进行了理化检验及综合分析，找出了造成大轴断裂原因－首先是由于存在淬火应力，而未得到及时回火，其次是原材料中存在严重的冶金缺陷。