铝合金异型材高温挤压变形规律的模拟研究

Aluminum-alloy hollow-section, with characteristics of light weight、high.special strength、high orrosion-resistance、、good conductor、easy to be formed, has.widely been utilized in fields of aviation and space flight、metallurgical and chemical processes、electrical and mechanical processes、communications and transportation、building and decoration. With the development of scientific technology, a great quantity of aluminum-alloy has been used for increasing the speed and decreasing.energy consumption in high speed train and light-duty car in developed countries..Also the national application in this field has just started, but it moves forward very quickly. More than ten projects of subway and light-duty rail are been designing and building. The consumption of aluminum-alloy hollow-section is expected to be from.fifty thousands to eight thousands ton per year, this tend is still forward..In most countries, the normal method of plastic forming for aluminum-alloy.hollow-section is extrusion at high temperature. The products are extruded directly through dies in heavy-duty oil presses with forming conditions of high temperature、 pressure and friction state. There are some problems in plastic deformation and molds design for complex construction of aluminum-alloy hollow-section and high mechanical features required. It is very important to research extrusion deformation laws of aluminum-alloy hollow-section at high temperature. For researches of extrusion deformation laws of aluminum-alloy hollow-section at high temperature, the usually studying methods are net、visual plastic deformation、 light plastic deformation、up and down limitation analysis、slipping curves field、.finite-element simulation etc. With the movement and development of computer.technology, the developing fields are computer finite units and nerve network.simulation. In this research, we used physical simulation and numerical simulation methods to simulate metal deformation. 1) Studying extrusion construction model of aluminum-alloy hollow-section at high temperature by simulation； 2) studying factors of simulating material effect on simulating features； 3) Studying the relation.between simulating materials and aluminum-alloys（6063、2024、7075）stress（σ）、 strain（ε）、strain-hardening exponent （n）、strain-rate sensitivity（m）； 4) constructional factors of extrusion dies effect on extrusion deformation laws of aluminum-alloy.hollow-section at high temperature..From the research, we have obtained following results：1) The composition of.“wax”to simulate the extrusion deformation of aluminum-alloy at high temperature.国家自然科学基金资助项目结题报告.8.are microcrystal wax 20～40%, resin 10～30%, ceramic clay 30～40%, additive 2～.10%； 2) simulating material－“wax”has quite good simulating characteristics at.room temperature to simulate extrusion deformation of aluminum-alloy.hollow-section at high temperature；3) mathematic model formula of flow stress of.aluminum-alloy （ 6063 、2024 、7075 ） at high temperature is.( ) ( ) 6 5 4 3 2 1.0 0./.0 / / a T a a T a a T a e + + + . . = ε ε ε ε σ σ & & ； 4) Extrusion trials of.simulation show that the shape、size and position of spreading holes have a great.effects on metal flow；The bridge construction has some effects on the strength of die；.The size of welding chamber has some effects on extrusion load；The bearing length.is relation not only to the flow rate of metal，but also to mechanical characteristics of.aluminum-alloy hollow-section..The research results are important not only to the theory research of metal.deformation, but also to developing new aluminum-alloy materials、new technology.and to improving the design theory of extruding dies.

铝合金异型材高温挤压变形规律研究，是国内外学者潜心研究的一个金属塑性成型基础理论课题。本项课题主要研究模拟材料组成、制备工艺、组织结构、模拟性能参数；以及在模拟挤压过程中，模具设计结构参数对挤压变形金属流动规律的数值关系；建立真实反映铝合金挤压变形的数学模型；提出铝合金异型材高温挤压变形和挤压模具设计的新观点与新理论。