W—Ni—Fe合金电子探针显微分析

阐述了用电子探针做显微分析的特点，拟定出了Ｗ－Ｎｉ－Ｆｅ合金断口分析和显微组织分析的方法；在断口分析中，讨论了断口样品制备、合金缺陷的观察和合会断裂的主要形式等问题；在显微组织分析中，讨论了抛光磨片制备、胶结相成分的测定、（ＮｉＦｅ）６Ｗ６Ｃ碳化物相的测定和Ｗ晶粒度的测定等问题。     

Ni-Fe合金电镀的研究

用Ni—Fe合金电镀工艺取代传统的Ni—W—P化学镀工艺，得到的Ni—Fe合金镀层比Ni—W—P镀层更均匀、更细致，同时具有更高的硬度、耐磨性和耐蚀性能。     

高Ni/Fe比W-Ni-Fe系重合金烧结行为

研究了钨质量分数为90%的高Ni/Fe比W-Ni-Fe系重合金在不同工艺参数(烧结温度、烧结时间等)下的烧结行为.研究结果表明:在相同烧结条件下,随粘结相中NiNe比增加钨合金烧结密度增加,致密化速率提高,同时烧结过程中W晶粒生长速率增大:当Ni/Fe比较低时,钨合金在循环烧结条件下难以实现完全致密化;但对高Ni/Fe比钨合金,循环烧结不仅可以获得比等温烧结更高的烧结密度,而且还可以有效地控制烧结过程中W晶粒的长大,获得细晶钨合金.     

Er-Fe-Ni合金膜在二甲基亚砜中电化学制备的研究

利用循环伏安法和恒电位电解法研究了室温条件下在LiClO4-DMSO(二甲基亚砜)体系中Er-Fe-Ni合金膜的电化学制备，实验结果表明：在0．1mol．L^-1ErCl3-0．1mol.L^-1FeCl2-0．1mol．L^-1 NiCl2-0．1mol.L^-1LiClO4-DMSO体系中，控制电位在-2.00V--2．60V范围内进行恒电位电解，可得到表面均匀、附着力强、有金属光泽的黑色非晶态Er-Fe-Ni合金膜，其中稀土Er的质量百分含量可达31．39％～41．63％。     

快速凝固Al-Fe-Ce合金显微组织及热稳定性的研究

采用单辊旋铸法制备Ａｌ－８Ｆｅ－４Ｃｅ（质量分数）合金薄带,利用透射电镜、能谱分析技术研究了该合金的急冷态和退火态组织,测定了合金在不同温度下退火后的显微硬度。急冷合金组织随冷速的不同而不同;３００℃退火态组织无明显变化;４００℃退火２ｈ后,晶界弥散相开始长大、聚集,但初生相变化甚微;４５０℃退火２ｈ后,初生相和晶间弥散相（分别为亚稳相Ａｌ６Ｆｅ和亚稳相Ａｌ２０Ｆｅ５Ｃｅ相）均进一步粗化。通过显微     

Ni-Co合金粉末的热压显微组织与力学性能研究

研究了Co含量(质量分数)分别为10%、20%、30%、40%、50%的Ni-Co合金粉末在不同热压温度下的显微组织与力学性能.研究结果表明:采用共沉淀-还原法制备的Ni-Co合金粉末烧结活性高,在700℃下就能热压致密化;在700℃至800℃之间热压时,晶粒长大较明显,热压温度超过800℃后,晶粒长大趋势减缓;随热压温度升高,Ni-Co合金综合力学性能下降,在700℃的热压温度下能获得最佳的综合力学性能;随Co含量增加,合金综合力学性能增强,Co含量增加到30%后,力学性能增强趋势减缓.700℃热压时含30%Co、40%Co、50% Co的Ni-Co合金的抗弯强度分别为1188.7 MPa、1220.5 MPa、1227.1 MPa.     

CoCrFeNiCuTix高熵合金的微观组织与耐腐蚀性能研究

采用真空热压烧结法制备了CoCrFeNiCuTi_x (x为摩尔比, x=0.25, 0.50, 0.75, 1.00)六元高熵合金, 研究了Ti含量对该高熵合金微观组织和耐腐蚀性的影响。利用金相显微镜、X射线衍射仪、扫描电子显微镜、HVS-1000B型数显显微硬度计和电化学工作站等设备测试和分析了CoCrFeNiCuTi_x高熵合金的组织结构和耐腐蚀性能。结果表明: 不同Ti含量(摩尔分数)的CoCrFeNiCuTi_x高熵合金, 物相都为面心立方结构, 组织主要为树枝晶; 随着Ti摩尔分数的增加, 高熵合金树枝晶组织减少, 硬度先增加后减小, x=0.50时, 合金的硬度值最大, 为HV 755;CoCrFeNiCuTi_x高熵合金的自腐蚀电位都正于45#钢, 耐腐蚀性先增强后减弱, x=0.50时, 其耐腐蚀性最优。     

W—Ni—Fe合金多孔材料的研究

研究了由细钨粉加1～2％Ni—Fe(wt),通过压制、预烧结、研碎、分级和强化烧结制预合金粉,再由合金粗粉加2％(wt)硬脂酸或0. 4％(wt)聚乙烯醇,通过成形、预烧结和烧结成W-Ni-Fe合金多孔材料的工艺。探讨了团粒强化烧结温度、粉末粒度、成形压力、烧结温度和时间等工艺因素对多孔W-Ni-Fe合金性能的影响。研制出具有最大孔径130. 7μm,相对透气系数1. 78×10~(-2)L/min·cm~2·mm·H_2O,开孔孔隙度26. 46％,抗弯强度141. 3MPa的多孔W-Ni-Fe合金多孔材料,经抗热震使用实验,证明能用于净化1523K和11. 8MPa的高温高压燃气。     

粉末冶金法制备过共晶Al-23Si合金的微观组织与力学性能

用Al-3Cu-1Mg-2Fe-23Si合金雾化粉末为原料,采用热压然后热挤压的方法制备Al-3Cu-1Mg-2Fe-23Si过共晶铝合金,利用金相显微镜、扫描电镜、万能电子拉伸机等研究该合金的显微组织与力学性能。结果表明:热压坯体中存在大量孔隙,相对密度为91%,抗拉强度为70 MPa,硬度为35HRB;经热挤压后相对密度达到99%,颗粒状硅相均匀弥散分布在基体中,硬度提高到72 HRB;进一步热处理后颗粒状硅相消失,合金硬度为84 HRB,抗拉强度达到219 MPa,断裂方式为脆性断裂。     

Ni-Fe-X基合金抗氧化性能的研究

用热压法制备了3种成分的Ni-Fe-X基合金,并在1 000℃和1 200℃进行了大气氧化试验。XRD,SEM,EDX和金相分析表明,Ni-11Fe-10Cu-6Al-3Sn(其中数据为质量分数)的氧化层最致密,主要由深色、浅色2种不同形貌和成分的混合氧化物组成,合金中的Cu具有较强的抗氧化性能,氧化铝的存在有效改善了氧化物结构。Fe-Ni合金氧化膜疏松,抗热震性弱,氧化膜与基体间有明显的裂纹,氧化膜主要是铁氧化物。     

几种典型双相不锈钢组织及性能特点及其对加工过程的影响

本文选择几种典型的双相不锈钢:S32707、S32750、S32205、S31803,在其工件上取样,采取了不同的热处理、热加工和热穿孔以及适当调整化学成分等试验方法,比较和研究了组织和性能特点及其对加工过程的影响。结果表明:两相比例和σ相的析出情况与热穿孔温度和冷变形的退火、固溶处理温度密切相关,S32707的二次相的析出速度和析出量远超于其他双相不锈钢。适当降低Cr、N含量,提高Mo含量,合理控制加热速度,终乳(锻)温度,并注意回炉加热和圆管坯中心钻孔的影响,可提高热加工塑性,防止开裂。试验中的S32707成品无缝管满足相关标准的要求。     

Design and fabrication of W-Mo-Ti-TiAl-Al system functionally graded material

To obtain a kind of functionally graded material (FGM) with a density gradient, the W-Mo-Ti-TiAl-Al system graded material was designed, and the powder metallurgy method was chosen for its fabrication. The sintering of W, W-Mo, and Mo-Ti alloys at low temperature was studied, and then the approximately wholly dense W-Mo-Ti-TiAl system FGM was achieved by one-step sintering at 1473 K for 1 hour under a pressure of 30 MPa. It was found that through sintering at 1473 K, mainly the mechanical mixtures of W and Mo were formed in W-Mo alloys. In Mo-Ti alloys, the newly designed Fe-Al sintering aids not only have an important effect on the densification of the alloys, but also contribute to the formation of the (Mo, Ti) solid solution. However, the solid-solution reaction that occurred in Mo-Ti alloys was still insufficient. During the sintering of Ti + TiAl, the chemical reaction of Ti + TiAl → AlTi₂ was induced within the sintered body. The W-Mo-Ti-TiAl-Al system FGM was finally fabricated by joining of the TiAl side of the sintered W-Mo-Ti-TiAl system FGM to metal Al with an Al-based brazing filler metal, and its density changed quasi-continuously within the large range from 17.15 to 2.70 g/cm³.     

Evolution of microstructure during fabrication of Zr-2.5 Wt pct Nb alloy pressure tubes

Microstructural changes occurring during the fabrication of Zr-2.5 pct Nb alloy pressure tubes by a modified route, involving hot extrusion followed by two pilgering operations with an intermediate annealing step, have been examined in detail. In the conventional fabrication route, the hot extrusion step is followed by a single cold drawing operation in which the cold work to the extent of 25 pct is imparted to the material for achieving the required mechanical properties. Tensile properties obtained at each stage of fabrication have been evaluated and compared between the two processes. The main aim of this work has been to produce a microstructure and texture which are known to yield a lower irradiation growth. Additionally, suitable annealing conditions have been optimized for the intermediate annealing which annihilates the cold work introduced by the first cold pilgering operation without disturbing the two-phase elongated microstructure. This elongated α+ β _I microstructure is required for obtaining the desired level of strength at 310 °C. The final microstructure and the crystallographic texture of the finished pressure tube have been compared with those reported for the conventionally processed material. presently on leave from BARC, is Postdoctoral Fellow, Department of Materials Science and Engineering, University of Cincinnati, Cincinnati, OH-45221.     

Observations on the microstructure and orientation relations in the vanadium-hydrogen system

Observations on the microstructure and orientation relations in the V-H system were made using optical, X-ray, and electron microscopy techniques. In the two phase α+ β region the axes of the β (bct) vanadium hydride were shown to be slightly tilted away from the cube axes of the α (bcc) vanadium. Metallographie observations of a polished (100) crystal showed two different surface features associated with the formation of the β hydride depending on the concentration. In the two phaseβ + γ region the orientation relation between the β(bct) phase and the γ (fcc) phase is such that the (100)_γ || (110)r and [001]_γ || [001]_γ.     

Effect of solution treatment under load on microstructure and fabrication of porous NiTi shape memory alloy by self-propagating high temperature synthesis

Abstract

Porous NiTi shape memory alloy was fabricated by self-propagating high temperature synthesis. Effects of solution treatment under load applied on the microstructure were investigated. The densities of the phases changed insignificantly with solution treatment but the intermetallic phases such as Ti₂Ni, Ni₄Ti₃ and Ni₃Ti₂ disappeared and the density of B2(NiTi) phase increased with the load applied during solution treatment. Consequently, porous NiTi SMA with ideal pore characteristics, high chemical homogeneity and high strength for hard tissue implants was obtained.     

梯度组织FGH96合金残留枝晶区的组织特征研究

采用梯度热处理工艺制备了具有梯度组织结构的FGH96合金亚尺寸盘坯, 对盘坯存在的残留枝晶区组织进行了研究。结果表明, 残留枝晶区实质上是一种γ′相未完全再结晶的组织区, 其呈区域性不均匀的分布于盘芯部位。残留枝晶区的形成与粉末颗粒冷凝组织的遗传性及未充分变形再结晶密切相关, 通过采用合适的热加工和固溶热处理工艺可以消除这种组织不均匀性。     

酸性球团还原过程中微观结构变化研究

在实验室模拟高炉条件下研究球团还原过程,采用X射线衍射仪(XRD)测定球团在不同还原温度下的物相组成,通过光学显微镜和扫描电镜(SEM)观察球团还原过程中微观结构的变化。研究结果表明:球团在还原过程中出现分层现象,由低温下外层磁铁矿-核心赤铁矿逐渐转变为高温下外层金属铁-核心浮士体;球团还原停滞现象首先由生成的渣膜包裹铁氧化物颗粒,引起还原速率降低,之后生成密实金属铁壳阻碍还原气体进入球团内部,进一步减慢还原速率。     

Studies on synthesis and microstructure evolution of multiphase in-situ composites based on Mo-Cr-Si system

This paper presents the results on in-situ synthesis of refractory metal-intermetallic composites (RMICs), Mo-16Cr-4Si and Mo-11Cr-9Si (wt.%) multiphase alloys and their characterization. The alloys were prepared from the oxides of molybdenum and chromium by their coreduction with Si as reductant. Exothermic nature of the synthesis reactions resulted in the formation of consolidated composite as a product in a single step. As-reduced alloys were remelted by arc melting and heat treatment was given. The evolution of phases and the microstructure were studied by XRD, SEM, and EDS analysis. The multiphase microstructure consist of the silicide phases (Mo,Cr)₃Si + (Mo,Cr)₅Si₃ for hypereutectic and (Mo,Cr)₃Si phase distributed in bcc matrix comprising essentially a solid solution of (Mo,Cr) for hypo-peritectic composition. Comparative studies of the synthesized alloys were also carried out to the composition, phases, microstructure, hardness and their oxidation behavior.     

S-型异质结光催化剂的制备和应用研究进展

近年来,研究者提出了一种新的S-型异质结光催化剂。S-型异质结光催化剂在光生电子空穴对的有效分离、无用电子空穴的复合、载流子的有效分离、保留强氧化-还原活性位点等方面有着显著的优点。综述了近年来,S-型异质结光催化剂的反应机理、制备方法,以及在水分解制氢、CO₂还原、污染物的降解、灭菌等应用方面的研究进展,提出了S-型光催化体系的发展前景和面临的挑战。