Study Of Layer Design And Wear Resistance Of Surface Layer Treated By PIII&D Duplex Technique

With the development of modern industry and new technology, the traditional surface modification techniques haven't met the requests of application under serious conditions. Therefore, two or more surface modification techniques need to be involved to produce a duplex treatment technique to meet the new requests of application, which are unobtainable through any individual surface modification technique. Especially in the field of avigation and aeronautics, it is exigent to improve the surface properties of components under wear, because the titanium and aluminium alloys are widely used to reduce the weight of industrial components. By this study, the author hope that the investigation can promote the development of duplex technology and offer effective technical methods to improve the wear resistance of soft alloy components. In this paper, PIII&D duplex treatments were conducted on the GCr15, Ti6Al4V and LY12 substrates, and the wear resistance of samples was investigated. Moreover, the load bearing capacity of coating-substrate systems was investigated by FE analysis of the indentation test to analyze the distribution of stress and strain in the coating-substrate system.The results show that the duplex treatment of GCr15 have a less effect on the load bearing capacity of system because of the thin film and structure like DLC coating by C ion implantation. The wear resistance of system can be drastically improved by PIII&D duplex treatment, and the wear life of sample by duplex treatment was increased by 5 times compared with the single DLC layer. The improvement of wear resistance is attributed to the increase of interface adhesion and decrease of residual stress.The load bearing capacity can be enormously improved by PIII&D duplex treatment for Ti6Al4V and LY12 substrates, mainly because that the transfer layer can decrease the stress and strain at the interface. The transfer layer of TiN/Ti(CN)x/TiC has the best effect for the gradient structure of elastic and plastic properties. The increase of thickness of transfer layer can also improve the load bearing capacity. For LY12, the increase of load bearing capacity is more obvious due to the softer substrate. The load bearing capacity has an important influence on the wear resistance of system. The transfer layer of TiN/Ti(CN)x/TiC by PIII&D can enormously improve the wear resistance of system not only due to the increase of load bearing capacity but also the decrease of residual stress at the interface. For Ti6Al4V substrate, the wear life of sample by duplex treatment was increased by 5 times compared with single DLC layer. The increase of thickness of transfer layer can also improve the wear resistance of system under high load, and the wear life of the sample with the 2.25μm transfer layer can be more than 60000 cycles under the load of 1 GPa. For LY12 substrate, the Ti/TiN/Ti(CN)x/TiC/DLC multi-layer gradient structure can enormously improve the load bearing capacity and wear resistance.In this paper, the coating design rules of PIII&D duplex treatment were concluded by the investigation of property. On the basis of substrate property and service condition, the substrate can be divided into soft substrate and hard substrate, and the corresponding PIII&D duplex treatments were offered.