原位合成Al_2O_3/FeAl复合材料的组织与性能

利用Fe-Al-Fe2O3体系的放热反应,原位热压合成了Al2O3/FeAl复合材料.借助XRD和SEM等研究了复合材料的物相组成和显微结构,以及Al2O3生成量对复合材料显微结构和力学性能的影响.结果表明:经1 250℃保温1.5h热压烧结的块体材料主要由FeAl及少量Al2O3相构成,FeAl基体为片层结构,增强相Al2O3分散在基体和晶界处.随着Al2O3含量的增加,基体晶粒尺寸明显减小,同时对材料起增强增韧作用.在Al2O3含量为1.2wt%时,试样的抗弯强度达到最大值1 329.22MPa;在Al2O3含量为0.8wt%时,试样的断裂韧性达到最大值29.95MPa·m1/2.此值正好处于金属与陶瓷材料性能链的断缺处.因此,本研究结果对于完善材料性能体系具有重要意义.

Microstructure and mechanical properties of Al2O3/FeAl composites prepared by in stiu synthesis and hot-pressing

Al2O3/FeAl composites were synthesized by in situ hot-pressing method ,using the exothermic reaction of Fe-Al-Fe2O3 system .Phases and microstructure of the as-prepared Al2O3/FeAl composites were analyzed by XRD and SEM ,respectively .Effect of Al2O3 con-tent on the microstructure and mechanical properties of the samples were investigated in de-tail .The results show that the as-sintered products are mainly composed of FeAl matrix and a little Al2O3 reinforced phase which formed by in situ hot pressing process at 1 250 ℃ for 1 .5 h ,SEM photographs show that the FeAl appears lamellar structure and the Al2O3 parti-cles tend to disperse on the matrix grain-boundary .With the increasing of Al2O3 content ,the grain size of the matrix decreased ,w hich is beneficial to enhance the toughness and strength of the products .The flexural strength and fracture toughness of the composites possesses the maximum value of 1 329 .22 MPa and 29 .95 MPa · m1/2 as the Al2O3 content is 1 .2 wt% and 0 .8 wt% respectively ,which is properly connected the performance link between metals and ceramics .And ,it is of significance to filling the gap of the mechanical property of the materi-als .