合金化填充材料Ni 对SiCP/6061Al 复合材料激光焊接焊缝显微组织的影响

以N i 片作为合金化填充材料对SiC_P/6061A l 金属基复合材料(SiC_P/6061A lMMC) 进行激光焊接, 研究了激光输出功率、焊接速度等焊接工艺参数对焊缝显微组织的影响。结果表明, 采用金属N i 片作为合金化填充材料对SiC_P/6061A lMMC 进行激光焊接, 可以在一定程度上抑制SiC 颗粒的溶解及针状脆性相Al₄C₃ 的形成, 并获得以Al₃Ni 等相为增强相的焊缝显微组织, 但在焊缝心部有粗大的气孔形成。      

Data mining to effect of key alloying elements on corrosion resistance of low alloy steels in Sanya seawater environmentAlloying Elements

In this paper,the relationship model between seawater environment,chemical composition and corrosion potential of low alloy steel is established and the distribution of corrosion potential of low alloy steel with changes in key alloying elements is excavated.The research was carried out with the following steps:Firstly,the relationship model between corrosion potential of low alloy steel and its influencing factors was established by data dimension reduction and artificial neural network(ANN).Secondly,key alloying elements of experimental steels were selected out by Pearson correlation analysis,then the corrosion resistance element model was visualized to show the effect of key alloying elements on corrosion potential of low alloy steel.Finally,corrosion potential of low alloy steel with the change of key alloying elements was classified and visualized by classification method.The mining results can reflect the validity of the proposed mining methods to a certain extent and provide an intuitive data basis for the development of high-quality and low-cost low alloy steels.     

镍基625合金电子束熔覆TiC涂层表面改性研究

目的 采用电子束表面改性技术对Inconel 625镍基合金进行电子束表面合金化(EBSA)处理,制备性能良好的TiC涂层,提高Inconel 625镍基合金的表面性能。方法 采用不同的电子束扫描速度(80、100、120 mm/min)在Inconel 625镍基合金表面制备TiC涂层,使用扫描电镜(SEM)拍摄合金区横截面进行EDS能谱分析,使用电子背散射衍射仪(EBSD)对合金层进行EBSD表征分析,使用显微硬度仪测量EBSA后的表面硬度,使用摩擦磨损试验机(RTEC)测试表面耐磨性、生成摩擦曲线并拍摄磨损表面的三维形貌。结果 从宏观形貌上来看,在80 mm/min扫描速度下涂层成形质量最好。微观组织测试结果表明,随着扫描速度的增大,平均晶粒尺寸增大。显微硬度测试结果表明,随着扫描速度的增大,表面硬度呈现降低的趋势,但涂层表面硬度均高于基材硬度。当扫描速度为80 mm/min时,TiC强化颗粒较多分布在表面,其表面硬度最高,为457HB,与基材相比,表面硬度提高了1.936倍。耐磨性测试结果表明,当扫描速度为80 mm/min时,磨损体积和磨损率最低,分别为0.913 1 mm<...     

Influence of focusing thermal effect upon AZ91D magnesium alloy weld during vacuum electron beam welding

The influence of focusing thermal effect upon the weld shape, microstructure and alloying elements distribution in the welded joints during vacuum electron beam welding on AZ91D magnesium alloy was studied. The results show that the focus state affects the offset of DOF, and further significantly affects the actual welding heat input in the process of vacuum electron beam welding. The sharp focusing state is characterized with higher welding energy density, but the welding energy density of defocusing state is lower. Therefore, the welding process with sharp focusing state and smaller calculation welding heat input can obtain the same weld penetration as the welding process is the conditions of defocusing state and larger calculation welding heat input. And the welding process of sharp focusing state and smaller calculation welding heat input can induce more strongly burning loss of Mg element than the conditions of defocusing state and larger calculation welding heat input. Then, which will affect the distribution of alloy elements in weld seam.     

机械合金化制备Mg-Ni合金氢化物电极材料的研究进展

Mg-Ni系合金作为一种重要的Ni/MH电池负极材料, 一直受到电池工作者的广泛重视. 本文对机械合金化方法制备Mg-Ni系合金作为Ni/MH电池氢化物电极材料的研究现状进行了全面介绍, 综述了Mg-Ni系合金的电化学性能、微观结构、吸放氢机理以及合金的制备方法, 如二元合金化、多元合金化、复合合金化、表面改性等, 并就机械合金化方法制备Mg-Ni系合金作为Ni/MH电池负极材料的研究前景进行了分析和展望.     

Ni-based superalloy surface alloying by double-glow plasma surface alloying technique

The double-glow surface alloying technique, also called the Xu-Tec/Xu-Loy process, is a novel technique in the field of surface alloying. This technique allows alloy layers with unique physical, chemical and mechanical properties, such as nickel-based alloy layers, stainless-steel layers and age-hardened surface high-speed steel layers to be formed at the surface of treated metallic materials. In this paper, recent research of the application of the double-glow plasma surface alloying technique in the formation of corrosion resistance alloy layers is briefly reviewed. The results of a study of Ni-Cr-Mo-Nb and Ni-Cr-Mo-Cu corrosion-resistant alloying layers as well as composite alloying layers with an electric brush plating Ni interlayer are reported.     

电子束冷床熔炼TC4合金工艺路线的优化选择

通过对电子束冷床熔炼TC4合金在转鼓进料和棒料进料两种进料工艺下熔化冷床的温度场的分布进行研究,为选择合理的熔炼工艺路线提供了理论依据。结果表明,转鼓进料熔炼的熔化冷床熔池温度波动较大,约为92~332℃,Al的烧损率为1.5%,TC4合金中Al分布不均匀,轧制板材出现局部贫、富Al现象。棒料进料熔炼的熔化冷床熔池温度较高且稳定,Al的烧损率为2%,TC4合金中Al分布均匀,轧制板材的组织成分也较为均匀。在实际的电子束冷床熔炼TC4合金生产中,应选择棒料进料熔炼工艺,且初始原料中合金化元素配比为Al占8%左右为宜。     

Fe70Zr10B20非晶合金的制备及其热稳定性和磁性能研究

采用机械合金化技术制备了Fe70Zr10B2。磁性非晶合金粉末。分析Fe70Zr10B20非晶合金的形成机制、晶化机制：研究Fe70Cr10B20非晶合金不同热处理温度下的磁性及球磨过程中样品的磁性。结果表明：Fe70Cr10B20非晶相的形成是由原子的扩散和晶格崩渍共同作用的结果；Fe70Cr10B20非晶合金的热致晶化模式为一次晶化；球磨过程厦非晶熟处理后样品的磁性与其结构、晶粒尺寸、应力和缺陷等因素有关。     

粉末冶金法制备Al-Pb合金微观组织分析EI

采用机械合金化与真空热压烧结制备Al-Pb合金,并通过热挤压变形细化显微组织。XRD检测分析表明:Al,Pb衍射峰随机械合金化的进行不断宽化,晶粒尺寸减小。SEM分析表明:球磨15h后可以得到合金粉末,其具有Pb粒子弥散分布于Al基体的复相结构。再通过550℃/20MPa真空热压烧结1h,可制备出Al-Pb合金块体。适当的热挤压工艺能够细化组织,减小Pb颗粒的尺寸。其抗拉强度可达231.6MPa,延伸率为17.6%。     

合金元素复合化对Ti_(2)AlNb合金高温抗氧化性能影响EI北大核心CSCD

Ti_(2)AlNb合金具有良好的工艺性能、综合力学性能和较低的密度等性能优势,是新型航空发动机的重要选材之一。为拓宽Ti_(2)AlNb合金的应用范围,需对传统Ti_(2)AlNb合金进行合金成分优化和工艺组织调控以进一步增强其高温抗氧化性能。本研究在传统Ti-Al-Nb三元合金体系基础上,综合设计Mo,Zr,W等合金复合化的方法提高Ti_(2)AlNb合金的抗氧化能力,通过对新型Ti_(2)AlNb合金在750℃和850℃的氧化增重行为分析、氧化层特征结构分析、表面氧化物种类和合金成分过渡分布分析等,发现Mo合金元素引起Ti_(2)AlNb合金在750℃上升至850℃时抗氧化性能的明显下降,Zr合金元素则始终保持着Ti_(2)AlNb合金良好的高温抗氧化能力;更为深入的截面试样SEM表征可将氧化层结构细分为氧化物层、富氧扩散层和组织演变层,Zr和W合金元素对850℃高温氧化过程中不同氧化层结构具有协同抑制作用,因此提出通过Zr和W合金元素复合的方法作为新型Ti_(2)AlNb合金抗氧化合金成分优化方向。     

The sintering process of a high permeability Ni-Fe-Cu-Mo alloy made by powder metallurgy

The magnetic permeability of a 77 Ni-14 Fe-5 Cu-4 Mo wt % alloy made by powder metallurgy is known to be improved by extending the sintering time considerably beyond that normally used. The room temperature measurement of resistivity during the sintering cycle of such an alloy clearly shows the overlapping stages of change that occur during the sintering process. The variation in resistivity and its relationship with the changes in density, in weight and in bend strength of compacts shows that de-oxidation of the constituent element powders occurs initially. De-oxidation is followed by sintering and alloying of the nickel and iron which is followed in turn by alloying of the molybdenum. The final stage involves the alloying of the copper and the elimination of pores.Electron microprobe analysis has shown that the copper does not alloy substantially until the copper particles melt, and that alloying is hindered if copper powder of large particle size is used. Sintering occurs more rapidly than alloying, but the rate of alloying is the most important factor in determining the electrical and magnetic properties of the alloy.     

汽车用钛合金表面双辉等离子Mo合金化层的制备及其摩擦磨损性能

为了改善钛合金的表面摩擦磨损性能,采用双辉等离子合金化法在汽车用近β型钛合金(Ti-5Zn-3Sn)表面制备了Mo合金层,通过微观组织观察及硬度、摩擦系数、磨损率测试等考察了合金化层的形貌以及摩擦磨损性能.结果表明:钛合金表面等离子合金化后,呈现出银白色,表面形貌很不平整,粗糙度和致密性得到提高.钛合金Mo合金化层与基体之间结合很好,没有出现不可控的断层以及裂纹.随着合金化层的逐渐深入,Mo元素占比慢慢降低.在Mo元素固溶强化作用的影响之下,钛合金表面硬度得到明显提高,有效地改善了钛合金表面摩擦学性能.随着Mo合金化温度增加,合金化层的硬度明显增加.合金化后钛合金表面硬度高,受压屈服极限大,黏着效应小,摩擦系数小,磨损率明显降低.     

机械合金化与非晶合金材料的研究进展

机械合金化是一种通过高能研磨实现的固相粉体加工技术.现已证明可以通过对纯组元混合粉或预合金粉进行机械合金化处理,合成包括非晶合金在内的多种平衡与非平衡合金相.主要评述了机械合金化法在非晶态合金材料研究领域的优势和特点,重点介绍了当前有关机械合金化致非晶化机理的研究成果以及未来这一领域的发展方向.     

粉末冶金TiVNbTa难熔高熵合金的组织和力学性能

将机械合金化(MA)与放电等离子烧结(SPS)相结合制备了难熔TiVNbTa高熵合金,研究了这种合金的机械合金化过程、相组成和显微组织,以及烧结温度和O、N含量对其力学性能的影响。结果表明:机械合金化后高熵合金粉末为BCC结构,放电等离子烧结成的块体高熵合金由BCC基体和FCC析出相组成,其析出相为TiN+TiC+TiO的复合物。烧结温度为1100℃的高熵合金具有良好的综合力学性能,压缩屈服强度达到1506.3 MPa,塑性应变为33.2%。随着烧结温度的提高,合金发生了从准脆性到塑性再到脆性断裂的转变。O和N含量的提高对高熵合金强度的影响较小,但是使其塑性显著降低。     

机械合金化合成Fe-Ni-C系非晶态合金

用机械合金化方法合成了Fe—Ni—C系非晶态合金,用X射线衍射仪对球磨不同时间的Fe—Ni—C系混合粉末进行了分析．结果表明：在Fe—Ni合金中加入C可促使其形成非晶;原子分数分别为Fe40Ni40C20、Fe60Ni20C20的混合粉末在一定的机械合金化条件下可获得非晶．     

Preparation of Cu-TiN alloy by external nitridation in combination with mechanical alloying

A copper alloy dispersion strengthened by TiN was prepared by external nitridation in combination with mechanical alloying. After mechanical alloying pure Cu and Ti powders, a Cu-3wt.%Ti solid solution was formed. These powders were nitrided at 1073 K, resulting in a TiN layer on the surface of the copper powders. Further mechanical alloying was very efficient in breaking down the TiN surface layers. A very fine uniform distribution of nanosized TiN was obtained. The resulting copper alloy had a grain size of about 150 nm in diameter after annealing at 1173 K in vacuum for 5.4 ks, and showed a very high room temperature hardness value of 251 kg mm⁻² which was independent of annealing temperature below 1173 K.     

Laser surface alloying of case hardening steel with tungsten carbide and carbon

Abstract

The laser surface alloying process was used to introduce two different alloying materials, tungsten carbide (WC/Co) and carbon, into the molten surface of a case hardening steel (16MnCrS5), to improve its hardness and wear resistance. The chemical composition and the resulting microstructure in the alloyed layers were of particular interest in this investigation, because the strengthening mechanism was strongly dependent upon the type and amount of the alloy material. For laser alloying with carbon the increase in hardness and wear resistance was based on the martensitic transformation in the composition range concerned. For alloying with tungsten carbide it was necessary to consider two different strengthening mechanisms, namely, martensitic transformation and precipitation of carbides. In both cases the grain refinement in the laser affected zone had an additional effect. Resistance to dry abrasive sliding wear was measured using a conventional pin-on-disc wear testing machine. For both alloy materials the wear rate was substantially lower than that of a substrate that had been laser remelted without alloying additions.

MST/1556     

Modification of Iron with Degradable Silver Phases Processed via Laser Beam Melting for Implants with Adapted Degradation Rate

In medical technology, implants are used to improve the quality of patients’ lives. The development of materials with adapted properties can further increase the benefit of implants. If implants are only needed temporarily, biodegradable materials are beneficial. In this context, iron-based materials are promising due to their biocompatibility and mechanical properties, but the degradation rate needs to be accelerated. Apart from alloying, the creation of noble phases to cause anodic dissolution of the iron-based matrix is promising. Due to its high electrochemical potential, immiscibility with iron, biocompatibility, and antibacterial properties, silver is suited for the creation of such phases. A suitable technology for processing immiscible material combinations is powder-bed-based procedure like laser beam melting. This procedure offers short exposure times to high temperatures and therefore a limited time for diffusion of alloying elements. As the silver phases remain after the dissolution of the iron matrix, a modification is needed to ensure their degradability. Following this strategy, pure iron with 5 wt% of a degradable silver–calcium–lanthanum alloy is processed via laser beam melting. Investigation of the microstructure yields achievement of the intended microstructure and long-term degradation tests indicates an impact on the degradation, but no increased degradation rate.     

Mo surface enrichment on a Fe–Cr alloy by electron beam irradiation

Mo alloying has been carried out on a Fe–Cr alloy by electron beam irradiation. It is shown that a Mo surface enrichment can be obtained in the range 2–8 at %. Scanning and transmission electron microscopy, X ray microanalysis and electron energy loss spectroscopy have been used to investigate the microstructures obtained after irradiation. Mo–Cr carbide and intermetallic X phase have been identified after alloying. The intermetallic phase is preferentially formed when the Mo content increases. It is concluded from electrochemical studies and potentiostatic attacks that the active and transpassive dissolution rates are closely related to the Cr content in the ferritic phase. This work must be also regarded as a first step towards the surface preparation of 316 S. S. by Mo incorporation to 304 S. S.     

Effect of beam interaction time on laser alloying with pulsed Nd–YAG laser

Abstract

Surface alloying of aluminium with nickel was carried out using a pulsed Nd–YAG laser. The effect of beam interaction time on laser alloying of aluminium with pulsed Nd–YAG laser has been studied. It was found that the beam interaction time of a pulsed laser has a significant effect on microstructure and properties of alloyed layers. The results indicated that with changes in the beam diameter, higher thickness of alloyed layer and higher microhardness are both obtained at a lower effective interaction time. When travel speed changes, the same conditions are obtained at a higher effective interaction time.