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1.
采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备了Mo-W合金涂层,利用场发射扫描显微镜(SEM)、电子能谱仪(EDS)、维氏显微硬度计分析测试了涂层组织、硬度,利用球-盘式摩擦磨损试验机研究了磨损载荷及频率对Mo-W合金涂层摩擦学性能的影响。结果表明:质量比为3:1的Mo、W机械混合粉喷涂后涂层中Mo、W元素质量比接近3:1。涂层组织致密,与基体结合为机械结合,表面平均显微硬度为563.2 HV0.1。Mo-W涂层的显微硬度、耐磨性和减摩性比基体45CrNiMoVA钢有所提高,且载荷越大,涂层的耐磨性和减摩性优势越明显。Mo-W涂层与Si3N4陶瓷的摩擦磨损机制以磨料磨损和氧化磨损为主。当磨损载荷变大和磨损频率变高时,疲劳剥落磨损表现明显。 相似文献
2.
采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备了Mo-W合金涂层,测试了涂层结合强度。利用电阻仪测试了涂层的导电性,用高压电弧装置对Mo-W涂层进行了大气环境不同放电电流的电弧烧蚀试验。通过场发射扫描电镜(SEM)、能谱(EDS)仪分析了涂层组织,使用X射线衍射(XRD)仪测试了涂层相组成。结果表明:Mo-W涂层与基体结合良好,但导电率较低,只有6.12%IACS。孔隙率是涂层导电性能较低的主要原因。随着放电电流增大,Mo-W涂层电弧烧蚀面积增大明显,呈现出2种烧蚀形貌;孔隙率越大、表面粗糙度越小,涂层耐电弧烧蚀性能越差。Mo-W喷涂层抗电弧烧蚀性能优于纯Mo喷涂层。 相似文献
3.
研究了Y元素对等离子W、Mo、Y共渗渗层的晶粒大小、厚度和渗层中W、Mo原子扩散系数的影响。研究发现,偏聚在晶界上的Y原子和少量金属间化合物Fe17Y2阻碍了渗层晶粒的长大,细化了渗层的晶粒。从扩散热力学角度,探究了Y元素对渗层厚度的影响。Y元素降低了表面W、Mo原子的活度,表面W、Mo原子的化学势降低,进而使表面与基体之间的化学梯度减小,W、Mo原子的扩散速率减慢,渗层厚度变薄。通过Fick第二扩散定律计算渗层中不同位置、浓度下的W、Mo原子扩散系数,结果表明W、Mo原子的扩散系数在10-13~10-14之间。 相似文献
4.
研究采用双层辉光离子渗金属技术在Ti-6Al-4V合金表面制备Mo基改性层的Mo扩散过程。通过观察渗层截面组织形貌,测定各种合金化元素的分布情况,着重分析不同温度下不同元素的加入对Mo扩散行为的影响。结果表明:在800~950℃下,Ti-6Al-4V合金离子渗Mo后所得改性层厚度、Mo平均扩散系数及相同浓度下Mo的扩散系数都随温度升高而升高;由于反溅射和Ti-6Al-4V基体相变等原因,1000℃时各参数反常;加入合金元素W和N使Mo的扩散系数有所降低,Mo的平均扩散系数在单纯渗Mo时为2.37688×10-4,W-Mo共渗时为1.47127×10-4,W-Mo-N共渗时为7.02681×10-5。 相似文献
5.
研究了Ir/Re喷管制备过程中的Ir/Mo互扩散问题。在电子探针测量的基础上,根据扩散理论和Ir-Mo相图数据,建立并推导Ir/Mo扩散模型和解。计算得到Ir3Mo相中的互扩散系数为:D=9.0×10-9exp(-1.46eV/kT)(cm2/s),Ir基固溶体中的互扩散系数为:D=5.0×10-10exp(-1.1eV/kT)(cm2/s)。确定喷管中Ir/Mo互扩散的特点,给出估算Ir3Mo相层厚的方法。确定Re在Ir3Mo相中的扩散主要是受Ir控制。 相似文献
6.
《热加工工艺》2018,(24)
采用超音速等离子喷涂技术在45Cr Ni MoVA钢表面制备Mo-W合金涂层,对涂层进行了从400~1000℃不同温度条件下的热处理,对不同处理状态下的涂层进行了电弧烧蚀试验。利用场发射扫描显微镜(SEM)、电子能谱仪(EDS)分析涂层组织和成分,利用维氏显微硬度计测试硬度,利用四探针电阻仪测定涂层电阻率。结果表明:热处理工艺可以改变合金元素的固溶度,但并不能明显消除喷涂层中孔隙等宏观缺陷;随着热处理温度升高,Mo-W喷涂层的显微硬度由563.2 HV0.1下降为460.6 HV0.1(1000℃),涂层的导电率呈现缓慢增加趋势;热处理温度为1000℃时涂层导电率最高,为6.42%IACS。在1000℃以下进行热处理,Mo-W涂层的耐电弧烧蚀性能有所提升。 相似文献
7.
采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备了Mo-W合金涂层,并与6061铝合金组成摩擦副,进行了磁场环境下的摩擦磨损试验。通过场发射扫描电镜(SEM)、电子能谱仪(EDS)分析涂层组织;采用X射线衍射仪分析涂层相组成;在不同磁感应强度(B)下测试了涂层显微硬度、表面氧浓度和表面温度。结果表明:随着磁感应强度的增加,Mo-W涂层的摩擦因数降低,磨损量有小幅减小。摩擦副表面的温度比不加磁场时有10~20℃的温升。磁场的施加对Mo-W涂层显微硬度值不会造成影响。Mo-W涂层磨损表面的氧含量随B的增加而变大。磨屑主要由表面覆有Al_2O_3的Mo-W合金微粒和Al_2O_3微粒组成,磨屑粒径随着B的增加逐渐变小。磁场在Mo-W涂层与6061铝合金的摩擦中主要有两个作用:一是提高摩擦副间的氧浓度,促进氧化磨损;二是使磨粒细化,降低摩擦因数。 相似文献
8.
目的在Nb-Ti-Si合金表面制备MoSi2涂层。方法先进行辉光离子渗Mo,再进行包埋渗Si。分析温度对渗Mo层表面形貌、厚度、元素互扩散的影响,以及渗Si后涂层的表面形貌和结构。结果在1100℃进行辉光离子渗Mo,渗Mo层与基体形成了显著的互扩散。对渗Mo层进行包埋渗Si后,所形成的涂层组织致密,具有多层结构,由外向内依次为MoSi2层、NbSi2层和Nb5Si3层,在MoSi2和NbSi2层之间存在(Mo,Nb)Si2互扩散区。结论通过辉光离子渗/包埋渗的方法,可以在Nb-Ti-Si合金表面制备Mo Si2涂层,且涂层与基体呈冶金结合,结合较好。 相似文献
9.
与传统Ni基单晶高温合金相比,高Mo强化Ni3Al基单晶高温合金具有富Al和富Mo的成分特征,即该合金具有低密度的优势。本文总结了该合金的凝固特性,并发现高Al的成分特征显著提高了平均液相扩散系数,即Ni3Al基单晶高温合金的平均液相扩散系数为10-8 m2/s数量级,比Ni基单晶高温合金高1-2个数量级。同时,高Al和高Mo的成分特征决定了合金具有枝晶间初生γ''相和富Mo相的末期凝固行为,这与Ni基单晶高温合金的枝晶间析出物(γ/γ''共晶和γ''相)明显不同,但高Al和高Mo的成分特征对凝固特征温度的影响较小。Mo在凝固时显著偏析于未凝固的液相,该偏析行为将降低高Mo强化单晶高温合金的雀斑形成倾向。合金凝固特性的研究将为单晶制备工艺与工程应用奠定基础。 相似文献
10.
《焊接》2017,(12)
为了提高单晶高温合金的高温耐磨抗氧化涂层,采用真空钎涂工艺制备了MCrAlY-Cr_3C_2复合涂层,并采用OM,SEM,XRD,EDS,EPMA和显微硬度试验等手段对涂层的组织、成分和硬度进行分析。结果表明,涂层主要由γ+γ',Cr_7C_3,Cr_(23)C_6,Ni_3Si和Cr_3Si组成,由于界面互扩散,界面上生成了含Mo,W的硅化物,且单晶基体的二次反应区中析出了各种形态的富Ta,Ti的碳化物。涂层中由于添加了碳化物强化相,显微硬度比单晶基体提高了近3倍,但分布不均匀;涂层与基体界面处由于固溶强化效果减弱,析出的硬脆相对硬度影响不大,因此硬度提升不够明显。 相似文献
11.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems. 相似文献
12.
Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone. 相似文献
13.
The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries. 相似文献
14.
《中国铸造》2014,(6):537-538
The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less. 相似文献
15.
16.
《机床与液压》2014,(12)
正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city. 相似文献
17.
《中国有色金属学会会刊》2014,(6)
正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis 相似文献
18.
<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of 相似文献
19.
《中国有色金属学会会刊》2014,(9):F0003-F0003
The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST. 相似文献
20.
After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation. 相似文献