ZrO2-13%Al2O3陶瓷薄壁件激光近净成形实验

采用同轴送粉激光近净成形系统,在纯钛基体上进行激光近净成形(LENS)ZrO2-13%Al2O3(质量分数)复合陶瓷的基础实验研究。分析了激光功率和扫描速度对激光近净成形陶瓷薄壁宏观质量(宽高、表面平整性和宏观裂纹)的影响规律,获得致密、无宏观裂纹的陶瓷薄壁件。利用扫描电镜观察了成形件的微观组织,结合电子探针(EPMA)和X射线衍射仪(XRD)分析了微观组织成分和ZrO2陶瓷激光加工前后相成分的变化。结果表明,激光功率和扫描速度对激光近净成形陶瓷单层高度和表面宏观质量具有重要影响,通过精确控制该两个参数能够获得良好的表面质量;不同的激光功率和扫描速度下,会产生横向和纵向两种不同的宏观裂纹;激光近净成形技术能够制备出致密并具有细小枝状晶组织的陶瓷;少量的Al2O3主要存在于晶界中,有利于抑制裂纹扩展。

Experimental Study on Ceramic of ZrO2-13% Al2O3 by Laser Engineered Net Shaping

ZrO2-13%Al2O3 (mass fraction) composite ceramic by laser engineered net shaping (LENS) with co-axial powder feeding is investigated on the titanium substrate. The effect of laser power and scanning speed on the macroscopic qualities (weight, height, surface and macrocrack) of ceramic by LENS is discussed, The dense、macrocrack-free ceramic thin-wall has been fabricated, the microstructure of ceramic has been evaluated using optical microscope, the composition distribution and the phase transformation before and after laser processing have been determinated by electro-probe microanalyzer (EPMA) and X-ray diffractometer (XRD). The results indicate that laser power and scanning speed have an important impact on the thickness of single layer and surface of ceramic, so good macroscopic qualities can be obtained by optimization of this two parameters. There may be two different macrocracks of horizontal and vertical by different laser powers and scanning speeds. The dense ceramic with fine dendritic crystal can be formed by the laser processing. Small amount of Al2O3 which mainly exists in the grain boundary is benefit to reduce cracks.