论文部分内容阅读
纳米陶瓷具有优良的室温和高温力学性能 ,如较高的抗弯强度、断裂韧性、耐磨性等 ,使其在切削刀具、轴承、高温发动机部件等诸多方面都有广泛的应用。利用纳米陶瓷的超塑性进行成形加工是实现复杂形状零件近净成形的重要手段。本文采用化学沉淀法制备了平均粒径 10nm ,且无硬团聚的 3Y TZP (3%摩尔氧化钇稳定的四方相氧化锆多晶体 )粉体 ,研究了不同密度素坯的热压烧结行为。 3Y TZP毛坯的超塑性拉深试验表明在 14 5 0℃压头速率为 0 2mm·min-1时可以实现半球形件的成形 ,其成形高度达到 5 7mm ;Al2 O3 ZrO2 纳米复相陶瓷的正挤压试验表明 ,这种典型的晶间 /晶内型纳米陶瓷在很高的温度下可以 0 . 5mm·min-1的压头速率进行挤压成形 ,在某种程度上可以满足工业成形的需求 ;Si3 N4 Si2 N2 O复合陶瓷通过烧结锻造可以成形陶瓷齿轮 ,其烧结温度为 16 0 0℃ ,超塑性锻造温度为 15 5 0℃。
Nanocrystalline ceramics have excellent mechanical properties at room temperature and high temperature, such as high flexural strength, fracture toughness, wear resistance, etc., making them widely used in cutting tools, bearings, high temperature engine parts and many other aspects. The use of nanocrystalline superplasticity of the forming process is to achieve a nearly net shape of the complex shape of an important means. In this paper, 3Y TZP (3% mol yttria-stabilized tetragonal zirconia polycrystal) powder with an average particle size of 10nm and no hard agglomeration was prepared by chemical precipitation method. The hot-pressing sintering behavior of the slabs with different density was studied. The superplastic drawing tests on the 3Y TZP blank indicate that the forming of the hemispherical part can be achieved at a head speed of 0 2mm · min-1 at 145 ℃, and the forming height reaches 57 mm. The positive Al2 O3 ZrO2 nanocomposite ceramics Extrusion tests show that this typical intergranular / intergranular nanocrystalline ceramic can be extrusion molded at a high temperature at a head rate of 0,5 mm · min-1, to some extent to meet the needs of industrial forming Si3 N4 Si2 N2 O composite ceramics can be formed by sintering forging ceramic gear, the sintering temperature is 16 0 0 ℃, superplasticity forging temperature of 15 5 0 ℃.