Ni基复合材料制备工艺与组织性能分析
发布时间:2018-03-28 03:26
本文选题:粉末冶金 切入点:镍基复合材料 出处:《天津工业大学》2017年硕士论文
【摘要】:镍基合金凭借其优秀的耐腐蚀性和耐热性,在航空航天、军事、化工、汽车制造业等领域都有着广泛的应用,但其本身存在硬度和自润滑性能较差等特点。本文采用粉末冶金法制备了 Ni-WC复合材料和Ni-MoS2复合材料,利用光学金相显微镜、X射线衍射、扫描电镜、能谱仪、洛氏硬度计等分析手段研究了 Ni-WC、Ni-MoS2复合材料的烧结工艺和增强相WC、MoS2的含量对Ni基复合材料组织性能的影响;并对Ni基复合材料进行热处理,研究了固溶处理和时效处理对Ni基复合材料组织性能的影响,优化热处理工艺参数。研究结果表明:1、采用粉末冶金法技术,在优化制备工艺参数条件下制备出了 Ni/WC镍基复合材料和Ni/MoS2镍基复合材料,材料致密度较高,增强相颗粒均匀分布在Ni基体中。2、当合金中添加WC颗粒后,烧结时,部分WC溶解在γ-Ni中,另一部分WC颗粒则均匀分布在合金中,冷却时,γ-Ni中析出大量的第二相,合金硬度随WC含量的增加而提高。当合金中添加MoS2时,随着MoS2含量的增加,合金中(γ-Ni+NiMo)共晶组织数量增加,合金中部分Cr溶解在NiMo金属间化合物中形成Ni(Mo,Cr),导致合金中M7C3碳化物数量的减少,第二相强化作用减弱,合金硬度较低。3、通过对烧结后样品组织分析可知:Ni60合金中主要由γ-Ni树枝晶、M7C3(M为Cr、Fe和Ni)碳化物、Ni3B颗粒和共晶组织(γ-Ni+Ni3B)组成;Ni-WC合金中主要由γ-Ni、碳化物M7C3、WC和共晶组织(γ-Ni+Ni3B)组成;Ni-MoS2合金中主要由γ-Ni树枝晶、M7C3碳化物、Ni3B颗粒、共晶组织1(γ-Ni+Ni3B)和共晶组织2(γ-Ni+NiMo)组成。4、Ni60合金经固溶处理后,合金主要由γ-Ni过饱和固溶体和碳化物M7C3组成;Ni60+10%WC合金经固溶处理后,合金主要由γ-Ni过饱和固溶体、碳化物M7C3和WC组成。固溶处理后的合金,在300℃~500℃之间进行时效处理时,合金中析出物数量不断增加,第二相强化效果显著,合金硬度上升,当时效处理温度为500℃左右时,合金的硬度达到最大值,继续提高时效温度,第二相不断聚集长大,弥散程度降低,第二相强化效果减弱,因此当合金时效处理温度在500℃~700℃时,合金的硬度逐渐下降。
[Abstract]:Nickel-based alloys have been widely used in aerospace, military, chemical, automobile manufacturing and other fields because of their excellent corrosion resistance and heat resistance. In this paper, Ni-WC and Ni-MoS2 composites were prepared by powder metallurgy method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy spectrometer (EDS) were used to prepare the composites. By means of Rockwell hardness meter, the sintering process of Ni-WCU Ni-MoS2 composite and the effect of the content of reinforced phase WCCnMoS2 on the microstructure and properties of Ni matrix composite were studied, and the heat treatment of Ni matrix composite was carried out. The effects of solution treatment and aging treatment on the microstructure and properties of Ni matrix composites were studied, and the heat treatment parameters were optimized. Ni/WC nickel matrix composites and Ni/MoS2 nickel matrix composites were prepared under the condition of optimized preparation process parameters. The densities of the composites were high, and the reinforcement particles distributed uniformly in Ni matrix. When WC particles were added to the alloy, the composites were sintered. Some WC dissolved in 纬 -Ni, the other WC particles distributed uniformly in the alloy. When cooling, a large number of second phases were precipitated in 纬 -Ni. The hardness of the alloy increased with the increase of WC content. When MoS2 was added to the alloy, the content of MoS2 increased. The amount of (纬 -Ni NiMo) eutectic structure in the alloy increases, and some Cr in the alloy dissolves in the NiMo intermetallic compound to form NiHMo-Cr-O, which results in the decrease of the amount of M7C3 carbides in the alloy and the weakening of the second phase strengthening effect. The hardness of the alloy is relatively low. The microstructure analysis shows that the Ni-WC alloy is mainly composed of 纬 -Ni dendrite M 7C 3N M carbide Ni _ 3B particles and eutectic microstructure (纬 -Ni Ni _ 3B), mainly composed of 纬 -Ni, M _ 7C _ 3U _ WC and eutectic microstructure (纬 -Ni _ 3B), which are mainly composed of 纬 -Ni dendrite (M _ 7C _ 3N _ 3C _ 3M) particles and eutectic microstructure (纬 -Ni). Ni3B) is mainly composed of 纬 -Ni dendritic M _ 7C _ 3 carbides and Ni _ 3B particles in Ni-MoS _ 2 alloy. The eutectic structure 1 (纬 -Ni Ni 3B) and eutectic structure 2 (纬 -Ni Ni Ni Mo). After solution treatment, the alloy mainly consists of 纬 -Ni supersaturated solid solution and carbides M7C3. The alloy is mainly composed of 纬 -Ni supersaturated solid solution, and the alloy is mainly composed of 纬 -Ni supersaturated solid solution. The composition of carbides M7C3 and WC. The amount of precipitates in the alloy after aging treatment at 300 鈩,
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