原位内生TiB2 /Al-4Cu复合材料半固态二次加热组织演化
Microstructure Evolution of Semi-solid In-situ TiB2 /Al-4Cu Composites During Reheating
张 磊 1,2,3, 陈薇娜2, 张晓楠2, 尧军平1,2
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作者单位:1. 南昌航空大学 航空材料热加工技术航空科技重点实验室, 江西 南昌 330063; 2. 南昌航空大学 航空制造工程学院, 江西 南昌 330063; 3. 北京科技大学 新金属材料国家重点实验室, 北京 100083
中文关键字:复合材料; 半固态; 二次加热组织; 组织演化
英文关键字:composites; semi-solid; reheating; microstructure evolution
中文摘要:对原位内生TiB2/Al-4Cu复合材料半固态坯料进行二次加热,利用光学显微镜,图像分析仪等手段,对坯料二次加热微观组织的演化进行了研究。结果表明,随着加热温度的升高和保温时间的延长,液相分数增加,α(Al)晶粒发生了长大和圆整化。TiB2/Al-4Cu复合材料合适的半固态重熔参数为:加热温度570~600 ℃,保温时间小于10 min。组织演化机制分析表明,二次加热初期,液相少,晶粒主要通过快速合并长大。随着加热温度的升高和保温时间的延长,液相增加,晶粒主要通过原子扩散缓慢长大并发生球化。
英文摘要:The microstructure evolution of semi-solid in-situ TiB2/Al-4Cu composites after reheating was studied by means of optical microscope and graphical analyzer. The results show that α(Al) grains grow up gradually and become more globular with the increase of isothermal temperature and holding time. The optimal process parameters are isothermal temperature range from 570 ℃ to 600 ℃ and holding time for less than 10 min. It is found that in the early stage of the whole reheating process, the volume fraction of liquid is low and grains grow up mainly through crashing and fusing. Grains grow up slowly and are sphericized mainly through elements diffusion with increasing volume fraction of liquid as the increase of the isothermal temperature and holding time.