景观建筑设计毕业论文参考文献
粉末挤压法是制取粉末冶金致密高性能材料的重要手段，国外对粉末 挤压成型工艺的研究和应用已十分广泛，国内在这方面的研究则相对 落后。昆明理工大学对双轮连续挤压及连续包覆的设备和工艺进行了 长期的研究，取得了许多突破性的进展。论文力图在此基础上结合粉 末铝基复合材料的优良性能，制备出高强轻质的粉末导线和界面结合 强度高、表面质量好兼而具备铝基复合材料各项优异性能的覆层导 线，以期获得工业性应用。 论文结合粉末的特性，对粉末塑性成 形的机理、粉末挤压制品的强化机制、粉末表面氧化物及颗粒强化材 料对粉末挤压制品的性能和成形性的影响进行了述评。对影响粉末挤 压成形性能的主要参数（挤压比、温度、颗粒度、变形速率、模具入 口形状以及润滑等）以及粉末包覆线成形的工艺作了定性的分析。利 用文献提供的屈服准则和力学模型，运用工程法和上限法得出了具有 工程意义的粉末挤压挤压力计算公式。在前期研究工作基础上，设计 了粉末线材及双金属、三金属包覆材连续挤压模拟实验的模具，并采 用此模具对粉末线材及包覆材在不同工艺参数下的成形作了实验性 研究。 论文给出了实验过程中挤压制品的抗拉强度与挤压比、颗 粒增强材料含量之间的关系，粉末挤压所需的实际挤压力与颗粒增强 材料含量、挤压比、挤压速度之间的关系等。分析了粉末线材及包覆 材挤压中所出现的废品及产生的原因。实验所得的铝粉末自氧化挤压 线材及用Al2O3和SiC 颗粒强化所得的线材 具有高的抗拉强度和良好的导电性能。所推导的金属粉末径向挤压挤 压力的计算公式，经实验验证，误差不超过±10％，满足工程要 求。 【英文摘要】 Powder extrusion is an important method for obtaining high-property dense products. The process of powder extrusion forming has been studied and developed extensively in foreign countries. KunMing university of science and technology has made great investment about bi-wheel continuous extrusion equipment and process. Many significant achievements have obtained. Based on these achievements and considered the high-property of powder Al-alloy, the dissertation tried to make high strength, low density powder wires and powder cladding products with metallurgical interface. These products were expected to obtain commercial using before long.Combining with characters of powder, the mechanic of powder plastic deformation, the strengthen cause of powder extrusion products, the effect of surface oxide and powder strengthen materials property and formability of powder extrusion products were introduced and discussed in this dissertation. The main parameters (extrusion ratio, temp
erature, article size, deformation velocity, configu
ration of die, lubrication etc.) effecting powder extrusion formability and forming process of powder cladding wire have been analyzed. Using engineering method and upper-bound method, this dissertation deduced a calculation formula for the load of powder radial extrusion. The formula was tested and verified by experimental results. Dies for powder wire, bi-metal and tri-metal cladding products were designed. Using these dies, formability of powder wire and cladding products in different processing parameters has been studied by experiments.The relations, such as the tensile strength of extrusion products to extrusion ratio and contents of powder strengthen materials, the practical load of powder extrusion to contents of powder strengthen materials, extrusion ratio and extrusion velocity, were given by this dissertation. Various defects in powder wire extrusion and powder cladding extrusion were analyzed and the causes v.ere given. Al self-oxide powder, Al2O3 -Al blending powder and SiC-Al blending powder extrusion wires obtained by experiments had high tensile strength as well as high conductibility. The margin of error between practical measuring results and calculation results using formula deduced in this dissertation was under+10%.