almntipcu中间合金及mg对al2551合金组织与性能影响word格式论文.docxVIP

下降近半，磨损机制也由混 合型磨损转化为单一的磨粒磨损;此外，合金的耐热、耐蚀性能也都获得超过 60%的显著改善。组织优化后缺陷的减少、 对基体割裂作用的减小以及 α-Al 的细晶强化作用， Mn、 Cu 等元素及高加 入量 Mg 的合金化作用，热处理后基体中的 M Si、AhCu 及其他析出强化 相的沉淀强化作用，对合金各性能的全面提升起到了重要作用。关键词: Al-25Si 合金， Al-企1 i-P-Cu 中间合金， Mg ，热处理，变质，强 化III-，EFFECTS OF AI-ì\i缸-Ti-P-Cu MASTER ALLOY AND Mg ON ì\i但CROSTRUCTURES AND PROPERTIES OF Al-25Si ALLOYABSTRACTWith the propuIsion of lightweighting for high power and turbocharged intemaI-combustion engine，more and more concem about Al-Si piston alloy， which is on the basis of Iight elements aluminum and silicon，is being eamed 仕om researchers. And hypereutectic high-Si aluminum aIloy often h出 as highas 22wt.% to 26wt.% Si-content，compared with lower Si-content Al-Si aIloy， the massive over-solution Si in the form of primary and eutectic Si in matrix， can greatly reduce density，thermal expansion coefficient and casting costs of this alloy，improve its volume stability，casting properties etc.，even these advantages can have a 缸rther play with the increase of Si content.But the moreSi con也nt increasing，the thicker Si phase will be，and the more difficult modification wiU be. At the same time，i臼 prope吗ries especially strength， ductility，wear resistance etc. wiI1 be damaged severely. Compared with other similar alloys，modification and streng出ening technology for bigh silicon aIuminum alloy is not mature enough at home and abroad，so its widespread useis limited .In the experiment，the high Si-content hypereutectic Al-25Si alloy wasVυused as the research object. Aiming its obvious advantages and disadvantages ，prepared a new type of AI-Mn-Ti-P-Cu master alloy to process ít，assisted with some Mg under certain technology and appropriate heat treatment process，to improve its microstructure and prope而es greatly and give fuIl play to the advantages brought by high Si-content. The mainly achievements are as folIows:The as-cast microstructure of experimentaI Al-25Si alloy contained: five-star or bulk primary Si，Jong-needle eut