高能球磨辅助热压烧结制备Cr_2AlC陶瓷的反应机理及力学性能

Reaction mechanism and mechanical properties of Cr_2AlC ceramic by high-energy milling and hot pressing sintering

以Cr粉、Al粉和C粉为原料,通过高能球磨及热压烧结反应,成功合成了三元化合物Cr2AlC块体陶瓷,并通过XRD和SEM测试详细分析了高能球磨及烧结过程中物相的转变及微观结构.结果表明:随着球磨时间的增加,产物中无新相生成,但原料的平均粒径在不断减小;高能球磨粉体经1 200℃保温90min的热压烧结可得到纯度较高的Cr2AlC致密块体;高能球磨辅助热压烧结合成的Cr2AlC块体的抗弯强度、断裂韧性和硬度等,相比于直接热压烧结合成的块体,分别提高了34.49%、11.86%和44.44%.

The ternary compound Cr2 AlC ceramic was successfully synthesized by a high-energy ball milling and hot pressing sintering using Cr, A1 and C as initial materials. The trans- forming phase and microstructure during the process of ball milling and sintering were inves- tigated by XRD and SEM in details. The results indicated that with increasing of the ball milling time, no any new phase was generated, but the average particle size of initial materials decreased. High purity Cr2AlC dense block could be synthesized at 1 200 ℃ for 90 min,after the milled powders were hot pressed. Compared with the hot pressed sintering directly,the flexural strength,fracture toughness and hardness of the Cr2AlC block synthesized by highenergy milling and hot pressing sintering are enhanced by 34.49% ,11.86% and 44.44% ,respectively.