文档介绍：光学级铝基复合材料热加工图研究
摘要
在欧美等发达国家,铝基复合材料的工业化生产已经开始,并且被列为2l 世纪新材料应用开发的重要方向。然而,由于在铝基体中加入了大量的硬质相颗粒,铝基复合材料的热加工性能与基体相比要下降很多,这在一定程度上阻碍了铝基复合材料的广泛应用;此外,由于增强体的加入使复合材料的组织变化与控制比传统材料更为复杂。因此,如何选择适当的热加工工艺,提高铝基复合材料的加工性能从而改善产品的显微组织成为目前所面临的关键课题。本文通过加工图对铝基复合材料的热加工性能进行表征,得到的主要结论如下:
SiC/2024 铝基复合材料随着温度的升高和应变速率的下降功率耗散效率有增大的趋势,这主要是由于温度的升高和应变速率的降低有利于动态再结晶的形核与长大。在绝大部分区域,SiCp/2024 铝基复合材料的功率耗散效率要高于铝合金,通过显微组织的观察证实颗粒的加入诱发铝基复合材料动态再结晶形核。
40%SiC/2024 铝基复合材料的加工图表明,该复合材料在实验范围内出现两个不稳定区域,一个位于低温高应变速率区,该区域的失稳颗粒周围形成孔洞造成的;另一个位于高温中等应变速率区,造成该区域失稳的因素可能是楔形开裂,加工时应尽量避免这两个区域。在温度为400℃480℃、~1s-1 压缩变形时,功率耗散效率最高,且与稳定区相对应;显微组织表明,在该区域颗粒与基体保持良好的界面结合,压缩过程中发生了动态再结晶,是40%SiC/2024 复合材料的最佳加工区域。
关键词:铝基复合材料,流变应力,热激活,动态材料模型,功率耗散,加工图
THE RESEARCH OF FLOW STRESS BEHAVIORS AT
ELEVELATED TEMPERATURE AND PROCESSING
MAPS FOR ALUMINUM POSITES
ABSTRACT
Industrialized production of aluminum posites (AMCs) has begun in the United States, Europe and other developed countries, and the material was classified as an important direction of new application materials for 21th century. However, due to the existence of hard particles in AMCs, hot-working ability of the material was much worse than the ability of aluminum alloy, which, to a certain extent, blocks the wide application of the material. Moreover, the existence of the particles will also make it more difficulty to control the microstructure changes of AMCs during hot deformation. Therefore, how to choose the appropriate hot deformation technology to improve the hot working ability of AMCs, and finally improve the microstructure of the production es a critical issue. In this paper, researches about the hot working ability of AMCs have been outspreaded by the ways of establishing of flow stress equations and developing processing maps, the main conclusion are as follows:
Steady-state flow characteristics were observed during hot deformation of SiCp/posites, and the flow stresses increase with the increasing of strain rate and the decreasing of temperature. The hot deforma