光固化增材制造碳化硅陶瓷的宏观缺陷检测及分析

Investigation of macroscopic defects of silicon carbide ceramics by stereolithography additive manufacturing

摘要

增材制造工艺解决了传统陶瓷制备工艺难以实现的复杂镂空结构的成形问题，能够实现更复杂的结构、更优异的设计，但是打印过程中缺陷难以避免。本工作以光固化增材制造的大口径碳化硅陶瓷为例，采用工业 CT 无损检测手段对部件出现的裂纹等宏观缺陷进行观察，分析光固化打印碳化硅陶瓷部件宏观裂纹的起始和扩展过程。结果表明，部件中的裂纹自弯角结构、结构孔等薄弱区域起始或进一步扩展，相关位置属于薄弱区域，更容易引发应力集中导致裂纹的产生；此处的打印及残粉处理应重点优化。通过结构优化、打印速率等工艺优化，尤其是薄弱区域的速度梯度优化，有利于避免裂纹等缺陷的产生。

Abstract

The additive manufacturing process offers a solution for fabricating complex hollow structures that are challenging to realize through traditional ceramic preparation methods. However，defects are often inevitable during the additive manufacturing process. In this study，silicon carbide ceramics with complex hollow structures are prepared using the stereolithography (SLA) additive manufacturing process. Industrial computed tomography (CT) non-destructive testing techniques are employed to observe and analyze macroscopic defects，such as cracks. The initiation and propagation mechanisms of cracks are investigated，and the influence of structural features on crack propagation is explored. The results indicate that printing corners and holes in the component are weak regions prone to stress concentration，which can lead to crack formation or further cracking. Therefore，particular attention should be paid to the printing process and the removal of residual powder. Through process optimization such as structure optimization and printing speed，especially the optimization of speed gradient in weak areas，it is helpful to avoid the occurrence of defects such as cracks.

关键词

光固化增材制造 / 碳化硅陶瓷 / 打印缺陷 / 有限元分析

Key words

stereolithography additive manufacturing / silicon carbide ceramic / crack defect / finite element method

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基金资助

国家重点研发计划项目(2021YFB3701500)