高压磨料水射流切割中材料破坏机理的分析

高压水射流切割是一种冷态切割技术,相比其他加工方式具有其独到的优势。对高压水射流切割试样的实验研究,用扫描电镜对切割断面进行观测,分析了高压水射流对材料的破坏方式。研究表明,射流对固体材料的破坏方式主要有两种：塑性破坏和脆性破坏,脆性破坏区的表面质量优于塑性破坏区。对水射流的破坏机理分析表明,射流对表层金属的硬化作用,导致了在起始阶段内,材料呈现脆性破坏,电镜扫描图上呈现层片状剥离的形貌,切割面相对光滑。在射流能量耗散之后,不足以实现表层硬化,磨料的磨削＂、犁耕＂使断面粗糙度上升。

Failure Mechanism of the Material Cut by High-pressure Abrasive Water Jet

As a kind of cold cutting technology, high-pressure water jet cutting has dlstmcnve advantages over other processing methods. Analysis of failure mode of the material cut by high-pressure abrasive water jet （AWJ） machine and observation under scanning electron microscope （SEM） were carried out. It indicates that there are two types of failure modes generated by AWJ, plastic failure and brittle failure and the surface quality of brittle failure is superior to that of plastic damage area. Analysis of failure mechanism of water jet shows that surface hardening of water jet induces the brittle failure in the initial period and the layer flake morphology which is relatively smooth. When the water jet gets diffused and the energy involved is insufficient to realize surface hardening, the grinding and ploughing function of abrasive roughen the surface.