等离子快速成形TiC增强高温合金基复合材料组织及性能研究

发布时间：2018-04-15 11:19

本文选题：等离子快速成形 + 高温合金基复合材料　；参考：《北京交通大学》2017年硕士论文

【摘要】：等离子快速成形技术可以直接成形形状复杂的金属原型或零件,可用于金属或梯度材料的快速成形与零部件的表面修复,是低成本直接快速成形制造金属结构件的有效途径。Inconel 718因其在650 ℃以内的屈服强度居变形高温合金的首位,且具有良好的抗疲劳、抗氧化、耐腐蚀和长期组织稳定性而得到广泛的应用。TiC因其熔点高、弹性模量高、硬度高、耐磨性好与高温稳定性好等优点而常被用作耐磨复合材料的增强相。本文分别以纯Inconel 718粉末与Inconel 718-23.5Ti-14.5镍包石墨(wt.%)、Inconel 718-29.5Ti-20.5 镍包石墨(wt.%)和 Inconel 718-37.5Ti-26.5 镍包石墨(wt.%)三种混合粉末为原料,利用等离子熔化沉积快速成形技术制备了 TiC为高温耐磨增强相、以主要组成相为γγ"-Ni_3Nb和固溶了大量合金元素的过饱和镍基固溶体的Inconel 718镍基高温合金为基体的高温耐磨复合材料。利用XRD、OM、SEM、EDS等手段分析了快速成形Inconel 718试样与复合材料的显微结构与相组成。结果表明:等离子快速成形Inconel 718试样组成相为y"-Ni_3Nb和γ-(Ni,Fe)固溶体;三种复合材料的组成相为TiC、γ"-Ni_3Nb和γ-(Ni,Fe)固溶体。复合材料组织细小且致密,γ"-Ni_3Nb依附于TiC初生相析出,并逐渐包覆初生TiC相。热处理制度对Inconel 718试样与复合材料组织影响有所不同,Inconel 718试样经固溶+时效处理促进了其γ"-Ni_3Nb相的析出,直接时效处理则不然,而两种热处理工艺对复合材料中γ"-Ni_3Nb相影响各不相同,但均导致复合材料发生组织粗化与析出相聚集连续的现象。利用显微硬度仪测试了复合材料的显微硬度,结果表明复合材料硬度随TiC含量的增加而上升。利用销-盘式常温磨损试验机测试了复合材料的常温干滑动摩擦磨损性能,结果表明在常温干滑动磨损条件下,Inconel 718试样常温耐磨性能较差,固溶+时效处理使其常温耐磨性能有所提高,而复合材料由TiC起抗磨骨干作用,常温耐磨性能随TiC含量的增加而上升,两种热处理工艺因对复合材料组织的影响均不利于了复合材料的常温耐磨性能。利用球-盘式高温磨损试验机测试了复合材料的高温干滑动摩擦磨损性能,结果表明在高温干滑动磨损条件下,Inconel 718试样磨损表面由于氧化磨损与磨粒磨损的共同作用,氧化膜遭接触应力破坏导致材料内部进一步发生氧化,并出现氧化膜剥落与转移的现象,而复合材料由于TiC耐磨增强相的引入,有效抵抗了接触应力所导致的磨粒磨损状况,并得以抑制材料内部的进一步氧化,使复合材料相较于Inconel 718高温合金具有较低的摩擦系数和磨损率,而过高的TiC含量不利于复合材料的抗载荷敏感性,因而适当的TiC耐磨增强相与Inconel 718高温合金基体含量可使复合材料表现出良好的高温耐磨性能,其中以Inconel 718-29.5Ti-20.5镍包石墨(wt.%)成分粉末为原料制备的复合材料具有最好的高温耐磨性能,应可用于高接触应力条件下的高温强磨损工况。
[Abstract]:Rapid plasma forming technology can form complex metal prototypes or parts can be used for direct forming, surface repair and rapid prototyping parts or metal gradient materials, is the low cost of direct rapid prototyping.Inconel effective way of manufacturing metal structures because of its 718 at 650 DEG C to yield strength in the first Ju superalloy, and has good anti fatigue, anti-oxidation, corrosion resistance and long-term stability of the organization and is widely used in.TiC because of its high melting point, high elastic modulus, high hardness, good wear resistance and high temperature has the advantages of good stability and is often used as reinforced wear resistant composite material. This paper YISHION Inconel 718 powder and nickel coated graphite (Inconel 718-23.5Ti-14.5 wt.%, Inconel, 718-29.5Ti-20.5) of nickel coated graphite (wt.%) and Inconel 718-37.5Ti-26.5 (wt.%) three nickel coated graphite mixed powder as raw materials, the use of plasma melting TiC prepared for the high temperature wear resistance enhanced deposition rapid prototyping system, which mainly consists of gamma gamma -Ni_3Nb and solid solubility of alloy elements of the supersaturated solid solution of nickel based Inconel 718 nickel based high temperature alloy for high temperature wear-resistant composite matrix. By using XRD, OM, SEM, EDS and other means of analysis the microstructure and phase composition of rapid prototyping Inconel 718 sample and composite materials. The results showed that the plasma rapid prototyping Inconel 718 samples are composed of Y -Ni_3Nb and gamma (Ni, Fe) solid solution; three kinds of composite materials are TiC, -Ni_3Nb and gamma gamma (Ni, Fe) solid solution. The structure of the composites is fine and dense, gamma -Ni_3Nb attached to the TiC primary phase precipitation, and gradually covering the primary TiC phase. The influence of heat treatment on Inconel composite tissue specimen and 718 different Inconel 718 after solution and aging treatment to promote the "gamma -Ni_3Nb precipitates, straight After aging treatment is not, and two kinds of heat treatment process on the composite gamma -Ni_3Nb phase effects vary, but are due to coarse structure and precipitation composite continuous gathered phenomenon. The microhardness of the composite was tested by microhardness tester, the results show that the increase of hardness of the composites with the content of TiC increased. By using the pin on disk wear tester at room temperature of the composite material at room temperature dry sliding friction and wear properties, the results show that in the condition of room temperature dry sliding wear, wear resistance of Inconel 718 samples at room temperature is poor, solution and aging treatment to the normal wear resistance is improved, and the composite material by TiC wear a key role to increase the wear resistance at room temperature, with TiC content increased, two kinds of heat treatment for the effect on the composite tissue are not conducive to the normal wear properties of the composites using ball - disc high. The high temperature test of composite dry sliding friction and wear properties of warm wear tester. The results show that in the condition of high temperature dry sliding wear, wear Inconel 718 surface due to oxidation wear and abrasive wear of the interaction, the contact stress damage caused by the oxide film material further oxidized, and the emergence of exfoliation of oxide films and transfer phenomenon. The composite materials with TiC wear resistant reinforcement is introduced, the effective resistance to abrasion of contact stress, and can inhibit the further oxidation of the composite materials, compared to the Inconel 718 high temperature alloy has low friction coefficient and wear rate, and the high content of TiC is not conducive to the anti load sensitivity of composite the material, thus TiC wear appropriate reinforcement phase and matrix content Inconel 718 superalloy can make the composites exhibit excellent wear resistance to high temperature, which The composites made of Inconel 718-29.5Ti-20.5 nickel coated graphite (wt.%) powder have the best high-temperature wear resistance. They should be applied to high temperature and strong wear conditions under high contact stress conditions.

【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB333

【参考文献】