Al_2O_3-MgAlON复合材料裂纹愈合机理研究  

Study on mechanism of crack healing in Al_2O_3-MgAlON composites

作　　者：杨道媛[1] 朱凯[1] 毋娟[1] 千粉玲[1] 鲁占灵[1] 

机构地区：[1]郑州大学材料科学与工程学院,河南郑州450001

出　　处：《耐火材料》2009年第1期31-34,共4页Refractories

基　　金：国家自然科学基金资助项目(50642008);河南省杰出青年基金(084100510003);河南省自然科学基金资助项目(0511052300)

摘　　要：以刚玉粉(≤3μm)和MgAlON粉(≤2μm)为原料,按w(刚玉粉)=75%,w(MgAlON粉)=25%的配比配料,制成3 mm×4 mm×36 mm的试样,在N2气氛中于1 500℃煅烧2 h,采用维氏硬度计在试样表面中心位置制造裂纹(压痕),然后在氮气保护下分别加热至1 000、1 100、1 200、1 300、1 500和1 550℃保温6 h进行愈合处理。通过愈合前后裂纹部位显微结构和物相组成的分析,探讨了Al2O3-MgAlON复合材料中裂纹的愈合机理和过程。结果表明:愈合前后Al2O3-MgAlON复合材料的物相组成和化学成分变化不大,裂纹的愈合机理主要是:以Al2O3和MgAlON的扩散填充为主,并伴随一定的晶粒长大填充;Al2O3-MgAlON复合材料的裂纹愈合过程大致为:裂尖钝化—岛状凸起—凸起接触及融合—次生裂纹收缩—完全愈合。Al2O3 -MgAlON composites were prepared by using corundum （≤ μm, 7,5 mass%） and MgAlON （ ≤2μm,25 mass% ） as the raw materials. The green compacts were pressed into 3 mm ×4 mm ×36 mm, and fired at 1 500 ℃ for 2 h in N2 flow. Cracks of the fired samples were prepared using a Vickers hardometer at the center of a sample surface,and healed at 1 000,1 100,1 200,1 300,1 500 and 1 550 ℃ for 6 h,respectively. The related mechanism of crack healing and its healing process were investigated by SEM and XRD. The results showed that：the phases and chemical compositions of the healed samples were similar to those of the unhealed samples,the crack healing was realized mainly by the migration of Al2O3 and MgAlON and the grain growth,which filled the cracks,and a crack-healing model was established as the following ：＂blunting deformation of the crack tips→formation of island-shaped salients→segmentation of the cracks→shrinking of the cracks→complete healing of the cracks＂.

关 键 词：Al2O3-MgAlON复合材料 显微结构 物相组成 裂纹愈合 

分 类 号：TQ175.71[化学工程—硅酸盐工业] TB32[一般工业技术—材料科学与工程]