等离子弧粉末堆焊熔覆材料的研究现状与进展

Current Status and Progress of Cladding Materials for Plasma Arc Powder Surfacing

自工业化应用以来,等离子弧粉末堆焊技术便受到机械工程领域工作者的广泛关注,并在机械零部件修复与再制造、零部件表面强化等方面取得了令人鼓舞的效果。随着现代科学技术的发展,等离子弧粉末堆焊设备被不断优化与改进,其自动化和数控系统水平不断提高,工业应用也更加便捷和高效,但当前等离子熔覆材料还是以自熔性合金粉末为主,高性能的新型熔覆材料研究报道相对较少。如何挖掘等离子弧粉末堆焊新型设备的技术优点,开发出满足当前对高强度、高真空、高温、耐磨、耐蚀等特殊性能需要的熔覆材料,是堆焊熔覆材料工作者所面临的重大挑战。近10年来,国内外的研究重点主要集中在自熔性合金粉末及其增强粉末的复合化设计,尽管已取得一些成果,但并未拓宽新的熔覆材料研究领域。最近几年,部分研究者开始将金属陶瓷基、纳米颗粒、自润滑、高熵合金等新型粉末作为熔覆材料,应用于等离子弧粉末堆焊的表面强化或修复中,但复合粉末选择原则、成分优化以及制备工艺等还有待进一步研究。除此之外,等离子粉末堆焊熔覆材料的研究尚缺乏一套系统的科学基础理论。目前,国内外等离子熔覆材料体系主要有:(1)合金化自熔性复合材料,利用一些功能性元素的固溶强化、析出强化、弥散强化和细晶强化等作用,改善熔覆层的组织和性能;(2)增强化自熔性复合材料,利用金属陶瓷基颗粒增强效应,提高熔覆层的性能;(3)稀土掺杂自熔性复合材料,发挥稀土特有的化学活性,净化熔覆层组织;(4)金属基自润滑复合材料,以金属或合金作为基相,固体润滑剂作为分散相,形成金属基自润滑堆焊熔覆材料;(5)高熵合金复合材料,将五种或五种以上的金属粉末混合组成复合粉末,形成高熵合金堆焊熔覆材料体系。除此之外,还有铜基、钛基、铝基、锆基和纳米等堆焊熔覆材料,借助这些材料的某些特性,使堆焊层实现耐磨、耐腐蚀、减摩、抗高温、抗热氧化和生物相容性等功能。本文介绍了等离子弧堆焊熔覆粉末材料设计应遵循的一般原则和成分优化的基本方法,归纳了堆焊熔覆层材料现有体系及其研究现状,分析了等离子弧堆焊熔覆材料存在的问题并展望了其发展趋势。

Since the industrial application of plasma arc powder surfacing technology,it has been widely concerned in mechanical engineering all over the world,and has achieved encouraging results in the repair of mechanical parts and the surface life of components.With the development of modern science and technology,plasma arc powder surfacing equipment is continuously optimized and improved,and its automation,systemization and numerical control level are continuously improved,thus its industrial applications are more convenient and efficient.However,at present,it is given priority to self-fluxed alloy powder with researching of cladding materials,and a few high-performance new cladding materials have been reported.How to discover the technical advantages of the new equipment for plasma arc powder surfacing,and meet the needs of special performances for cladding material,such as high strength,high vacuum,high temperature,wear-resistant,corrosion-resistant,etc.,which is big challenge for workers on surfacing welding cladding material.In nearly a decade,the researcher focus at home and abroad is mainly concentrated on the compound design of self-fluxing alloy powder and its reinforced powder.Although some achievements have been achieved,it has not broadened the new research fields of cladding materials.In recent years,some researchers have begun to apply new powders,such as metal ceramic base,nano-particles,self-lubricating and high entropy alloys as cladding materials,which have been applied to the surface strengthening or repair of plasma arc powder surfacing,but the selection principle,composition optimization and preparation processes of composite powder need to be further research.In addition,it is lack of a set of systematic and scientific theory for the research of plasma powder surfacing welding cladding material.At present,the domestic and international plasma cladding material systems mainly include:(1)alloying self-fluxed composite materials by adding some functional metal elements,which can improve the microstructure and properties of cladding layer by the solid solution strengthening,precipitation strengthening,dispersion strengthening and fine grain strengthening of added elements;(2)reinforced self-fluxed composite mate-rials by metal ceramic particles,which can improve the performance of cladding layer;(3)rare earth doped self-fluxed composite materials,which can purify the cladding layer microstructure by exerting the unique chemical activity of the rare earth;(4)metal-based self-lubricating composite materials,which consist of a metal or alloy as the base phase and a solid lubricant as the dispersed phase;(5)high entropy alloy compo-site materials,which mixed five or more metal powder.In addition,there are metal-based cladding materials,such as copper-based,zirconium-based,titanium-based,aluminum-based,and nano-based.With the help of some properties of these materials,the surfacing layer achieves functions such as wear resistance,corrosion resistance,anti-friction,high temperature resistance,oxidation resistance and biological compatibility.This paper introduces the general design principle and basic composition optimization methods of cladding powder materials.The existing systems and research status of cladding materials are summarized and the problems of plasma arc surfacing welding cladding material are analyzed,and its developing trend of the surfacing welding cladding materials is prospected.