摘要
The effect of incorporating limited-diffusivity elements such as Fe and Ti on thermal stability of the nanocrystalline Al alloy was investigated.Al−10wt.%Fe and Al−10wt.%Fe−5wt.%Ti alloys were fabricated.The initial mixtures of powders were milled for 100 h in vacuum.The bulk samples were fabricated from the milled powders in a high frequency induction heat sintering(HFIHS)system.The milled powders and the bulk sintered samples were characterized by X-ray diffraction(XRD),Vickers microhardness,field emission scanning electron microscopy(FESEM-EDS)and transmission electron microscopy(TEM).The observations indicated that Fe and Ti were completely dispersed in the matrix to form a supersaturated solid solution(SSSS)with Al.Additionally,the inclusion of alloying elements led to an increase in hardness and yield strength of the alloy by 127%and 152%,respectively.The elevated temperature compression tests were carried out to evaluate the thermal stability of the alloys.The Al−10wt.%Fe−5wt.%Ti alloy revealed the optimum thermally stable behavior of the three alloys studied.The incorporation of Fe and Ti improved the thermal stability of the developed alloys through inhibiting the grain growth,hindering dissolution and growth of second phases(such as Al13Fe4 and Al13Ti),and forming a stable solid solution.
为研究加入Fe和Ti扩散系数有限的元素对纳米晶铝合金热稳定性的影响,制备Al−10%Fe(质量分数)和Al−10%Fe−5%Ti(质量分数)合金。将初始混合粉末在真空下球磨100 h,用高频感应加热烧结系统将球磨后的粉末制备成块体样品。采用X射线衍射仪、维氏显微硬度仪、场发射扫描电子显微镜和透射电子显微镜对球磨后的粉末和烧结后的块体样品进行表征。结果表明,Fe和Ti完全分散在基体中,与Al形成过饱和固溶体。另外,合金元素的加入使合金的硬度和屈服强度分别提高127%和152%。通过高温压缩试验评估合金的热稳定性,结果显示3种合金样品中Al−10%Fe−5%Ti合金的热稳定性最好。Fe和Ti的加入抑制合金的晶粒长大,阻碍第二相如Al13Fe4和Al13Ti的分解、长大,形成稳定的固溶体,从而提高合金的热稳定性。
