约束电爆喷射沉积方法的机理研究

Constrained electrical explosion spraying deposition is one of the new approach of Additive Manufacturing，which have advantages of high speed of spraying particle，deposition layer could get to metallurgical bonding，suitable for the small diameter in-bore spraying because of its small device size and also easy to control deposition layer. Base on the approach of conduct current by gas discharge invented by applicants and technology of ablative material constrain products of electrical explosion spraying，embrace the basic theory problems of formation，characteristic and interaction with substrate of spraying particle in process of electrical explosion spraying deposition.We will mainly research Principle of energy input and process control of Electrical explosion conductor materials；Distribution and variation rules of spraying particles’size，portion and energy in spraying space；Regulation mechanism of structure and energy input of constrained tube；The interaction mechanism of spraying particle and substrate and the technological conditions of forming the metallurgical bonding interface.At last，basic design principle of ablative material electrical explosion constrained tube will be formation；complete production of electrical explosion spraying prototypical device possessed engineering application value；could use the wire and powder as the feedstock as well as control the performance of deposition layer and adjust character of spraying particles through matching the technology parameter.Because of the implement of this project , constrained electrical explosion spraying deposition method is expected to become an integral part of new member of surface engineering, At the same time, will lead a new method of small parts spraying deposition.

约束电爆喷射沉积是一种增材制造新方法，具有喷射粒子速度高，沉积层可形成冶金结合，设备尺寸小适于小直径孔内壁喷涂，易于控制适于小零件的喷射成型。基于申请者发明的气体放电电爆方法，以及消融材料约束电爆炸喷涂产物的技术，围绕电爆喷射沉积过程的喷射熔滴形成、特性及与基体的相互作用等所涉及的基础理论问题，重点研究：电爆导体材料能量输入原理及过程控制；喷射熔滴的尺寸、份额和能量属性在喷射空间的分布变化规律，以及约束腔结构和能量输入的调控作用机制；喷射熔滴与基体的相互作用机制，及形成冶金结合界面的工艺条件。最终能够形成消融材料电爆约束腔基本设计原理，研制出具有工程应用前景的设备样机；能针对丝、粉等不同形态及物理性能的材料导体，通过工艺参数匹配，调控喷射熔滴特性、控制沉积层性能。本项目的实施，可使约束电爆喷射沉积方法有望成为表面工程领域不可或缺的新成员；同时将引领一种新的小零件喷射成型方法。

电爆喷射沉积是一种增材制造新方法，具有喷射粒子速度高，沉积层可形成冶金结合，设备尺寸小适于小直径孔内壁喷涂，易于控制适于小零件的喷射成型。研究团队围绕电爆喷射沉积过程的喷射熔滴形成、特性及与基体的相互作用等所涉及的基础理论问题开展工作。.提出了约束电爆喷射沉积的新方法。采用在约束腔内开槽的方式,实现对喷涂粒子的约束调控。分析认为喷涂材料阻性加热所导致的“热膨胀效应”和沿面击穿电弧伴生的“压力效应”及其后续在约束腔内的发展变化,主导着约束腔对喷涂粒子的约束调控作用,影响喷涂粒子的沉积行为及涂层的形成。.研究了丝导体和粉末导体的能量沉积特性及模式。对于丝导体,通过改变初始电压和丝径的方式,控制材料在欧姆加热过程中的熔化、气化状态,调节能量沉积模式达到慢电爆模式,得到的涂层最为均匀致密。对于粉末电爆而言,存在两种能量沉积模式:平滑震荡模式和突变模式。在平滑震荡模式下,无法形成高质量涂层,而在突变模式下涂层最为均匀致密。可通过同时提高充电电压和减小粒径的途径,控制粉末体系电阻的演变特性以达到抑制旁路电流过早形成的目的,实现粉末能量沉积模式由平滑震荡式向突变式转变,进而改善涂层质量。.利用自行设计的喷涂粒子收集装置和喷涂粒子飞行特征测试系统,对喷涂粒子形成后的喷射飞行特性（尺寸分布、温度、速度、空间分布规律以及入射角度）及其沉积行为进行测试分析。发现喷涂粒子的尺寸分布对其飞行轨迹有着显著的影响,尺寸分布均匀、飞行轨迹统一的喷射粒子是获得理想涂层的关键。.基于对电爆电爆喷射沉积机制的理解，针对工程需求设计开发了管内壁约束电爆喷涂设备样机、带载丝电爆喷涂样机以及约束电爆石墨烯制备低维纳米碳样机。