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1.
La2O3弥散强化钨合金的组织性能研究 总被引:1,自引:0,他引:1
采用机械球磨的方法制备W-1%La2O3(质量分数,下同)复合粉体,将粉体在1823K烧结1h制备出La2O3增强钨合金。对材料的显微组织结构和力学性能进行分析,结果表明:显微组织均匀,氧化镧主要以微小的颗粒分布在钨-钨界面上,钨晶粒尺寸约为10μm~15μm:La2O3增强钨合金的抗弯强度值475MPa,在相同密度条件下,相对纯钨烧结体提高了35%。抗弯断口形貌表明,加入氧化镧颗粒后,钨合金的断裂方式发生了变化,由钨晶粒断裂为主转变为穿晶断裂和沿晶断裂的混合,同时分析讨论了氧化镧颗粒对合金组织性能的影响。 相似文献
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以喷雾干燥法制备的不同稀土Y含量的90W-7Ni-3Fe复合粉末为原料,在不同的烧结温度下制备出不同稀土含量的钨合金,采用XRD、SEM和EDX研究了稀土Y在90W-7Ni-3Fe合金中的存在形态和分布规律。结果表明:稀土Y以Y2O3的形式存在于合金中,且钨颗粒内部未发现稀土Y的存在。Y的添加量为0.4%时,以富Y颗粒的形式分布在钨颗粒与粘结相之间;当添加量为5%时,在粘结相中形成了富Y区域。添加稀土Y可以有效地细化钨颗粒。 相似文献
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通过粉末冶金法制备了添加稀土元素La,Ce的93W-4.9Ni-2.1Fe合金,研究不同稀土元素及不同稀土含量对高密度93钨合金静、动态力学性能的影响规律。结果表明:由于稀土元素La,Ce的加入,减少了杂质元素氧在钨-粘结相界面的偏析,减小了钨颗粒的连接度,从而改善了钨合金的力学性能,尤其是合金的动态力学性能得到显著提高,稀土元素的合理添加量为0.10%~0.15%。 相似文献
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结合机械合金化和热压烧结技术制备的多相Mo-12Si-8.5B合金是由钼固溶体(α-Mo)和金属间化合物(Mo3Si和Mo5SiB2)组成的复合材料。合金的微观组织是Mo3Si和Mo5SiB2以颗粒形态弥散分布在具有连续结构α-Mo基体的晶粒内和晶界处。纳米尺度的La2O3颗粒主要分布在Mo-12Si-8.5B合金中α-Mo相的晶粒内,部分存在于Mo3Si和Mo5SiB2颗粒内。纳米La2O3颗粒的掺杂同时细化了α-Mo基体的晶粒和Mo3Si与Mo5SiB2相的颗粒从而使合金具有细小的微观组织,合金内α-Mo、Mo3Si和Mo5SiB2相的平均晶粒或颗粒尺寸均小于1μm。结合微观组织观察及力学性能试验结果,对Mo-12Si-8.5B合金中存在的细晶强化、固溶强化和颗粒强化多重强化效果的耦合作用进行了量化分析。 相似文献
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研究了快速-热挤压工艺对细晶93W-4.9Ni-2.1Fe、细晶93W-4.9Ni-2.1Fe+0.03%Y以及传统粗晶93W-4.9Ni-2.1Fe合金的显微组织和力学性能的影响。结果表明:经过快速热挤压后,合金的综合力学性能较烧结态合金显著提高,而且初始晶粒尺寸对挤压后合金性能影响非常显著,在相同的挤压条件下,挤压态细晶93W-4.9Ni-2.1Fe+0.03%Y的抗拉强度达到1570 MPa,延伸率为6.5%,硬度HRC45.2;而挤压态传统93W-4.9Ni-2.1Fe合金的抗拉强度、延伸率和硬度分别只有1260 MPa、5.6%和39.1。显微组织观察分析表明,与传统钨合金相比,在相同变形量的情况下,细晶93W-4.9Ni-2.1Fe+0.03%Y钨合金的纤维化程度更高,钨颗粒长细比达到6.8。TEM观察表明挤压后细晶钨合金的钨相形成了亚晶组织,而传统钨合金有大量位错缠结于钨相中;此外,由于充分的动态回复-再结晶,细晶和传统钨合金的粘结相位错密度很低。 相似文献
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研究了快速-热挤压工艺对细晶93W-4.9Ni-2.1Fe、细晶93W-4.9Ni-2.1Fe+0.03%Y以及传统粗晶93W-4.9Ni-2.1Fe合金的显微组织和力学性能的影响。结果表明:经过快速热挤压后,合金的综合力学性能较烧结态合金显著提高,而且初始晶粒尺寸对挤压后合金性能影响非常显著,在相同的挤压条件下,挤压态细晶93W-4.9Ni-2.1Fe+0.03%Y的抗拉强度达到1570MPa,延伸率为6.5%,硬度HRC45.2;而挤压态传统93W-4.9Ni-2.1Fe合金的抗拉强度、延伸率和硬度分别只有1260MPa、5.6%和39.1。显微组织观察分析表明,与传统钨合金相比,在相同变形量的情况下,细晶93W-4.9Ni-2.1Fe+0.03%Y钨合金的纤维化程度更高,钨颗粒长细比达到6.8。TEM观察表明挤压后细晶钨合金的钨相形成了亚晶组织,而传统钨合金有大量位错缠结于钨相中;此外,由于充分的动态回复-再结晶,细晶和传统钨合金的粘结相位错密度很低。 相似文献
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采用稀土微合金化和液相强化烧结技术制备细晶93W-4.9Ni-2.1Fe+0.03%Y合金。研究在快速热挤压形变强化后,时效热处理对挤压态细晶93W-4.9Ni-2.1Fe+0.03%Y合金显微硬度和组织演变的影响,并与相应条件的传统钨合金进行对比。结果表明,随着退火温度的升高,2种钨合金钨相的显微硬度大大降低。EDS分析表明,随着退火温度的升高,钨合金粘结相中钨含量逐渐增加,其中细晶钨合金经过1200 ℃退火处理后,粘结相钨含量高达26.11%,而传统钨合金在1350 ℃退火处理后含量最高,达到28.14%。显微组织观察表明,退火有利于降低W-W连接度和细化钨颗粒;与传统钨合金相比,高温退火后,细晶钨合金的粘结相体积比更高且分布更为均匀 相似文献
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The effect of swaging on the microstructure and mechanical properties of 93W-4.9Ni-2.1Fe alloy was investigated. The alloy was prepared by liquid-phase sintering under hydrogen atmosphere followed by vacuum heat treatment and swaging at 600 °C with different area reductions (ranging from 15.0% to 84.8%). The as-swaged alloy with area reduction 84.8% exhibits the highest ultimate tensile strength (about 1490 MPa) and the lowest elongation (about 2.5%), which has been attributed to higher fraction of tungsten cleavage. For the as-sintered alloys, the fracture modes are a combination of the ductile rupture of W-Ni-Fe-Co matrix, transgranular cleavage of the tungsten particles, W-W interfacial segregation and W-M interfacial debonding, whereas transgranular cleavage of the tungsten particles is the main characteristic in the as-swaged alloy. Transmission electron microscopy images indicate that tungsten grains and W-Ni-Fe-Co matrix phase are composed of high-density dislocations. Based on the results, when running the swaging of 93W-4.9(Ni, Co)-2.1Fe alloy at 600 °C, the strengthening mechanism can be mainly due to the working-hardening. 相似文献
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《Corrosion Science》1999,41(2):291-304
The anodizing behaviour of sputter-deposited Al-4 at.% Au-1 at.% Cu and Al-1.6 at.% W-0.6 at.% Zn alloys has been examined by Rutherford backscattering spectroscopy and transmission electron microscopy. Initially, a uniform, amorphous alumina film, free of copper and gold species, is formed on the Al-Au-Cu alloy; at the same time, a thin alloy layer, beneath the anodic film, is enriched in copper and gold. The uniform film growth is eventually terminated by generation of oxygen at gold-rich particles at, or near, the alloy/film interface, leading to bubble formation, subsequent rupture of the film and release of oxygen. Film growth on the Al-W-Zn alloy causes mainly enrichment of tungsten in the alloy, with the limited enrichment of zinc contrasting with the behaviour of Al-Zn alloys. Uniform film growth proceeds to high voltages with incorporation of mobile tungsten and zinc species into the film. 相似文献
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氧化镧弥散强化钼合金裂纹扩展的TEM原位观察 总被引:2,自引:0,他引:2
采用透射电子显微镜动态拉伸技术对氧化镧弥散强化钼合金的裂纹扩展过程进行原位观察.发现裂纹的扩展模式受基体晶粒尺寸与氧化镧颗粒的形状和尺寸影响.裂纹尖端遇到非常细小的晶粒时会发生沿晶界扩展;裂纹尖端遇到棒状微米级粗大氧化镧颗粒时,裂纹穿过氧化镧颗粒扩展;遇到椭球状亚微米级氧化镧颗粒时,裂纹越过氧化镧颗粒扩展,并发生裂纹扩展方向的偏转;而当裂纹扩展到细小的球状纳米级氧化镧颗粒时会被阻止,裂纹以"Z"字型或跨接的方式继续扩展.根据实验结果从裂纹扩展方式和能量耗散角度对氧化镧弥散钼合金的细晶增韧和颗粒增韧机制进行分析和讨论. 相似文献
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利用机械球磨、放电等离子体烧结法制备了质量分数(%,下同)为W-(10~30)V-(10~30)Cr的三元合金,对烧结后的合金进行了显微结构和室温力学性能研究。结果表明,采用放电等离子体烧结可以制得相对密度为99.7%的W-30V-20Cr合金,其实际密度比烧结纯钨降低了49.74%;显微结构分析表明V、Cr可以很好地合金化,形成塑性连续相,包裹在钨分散相的周围,很好地改善了钨合金的力学性能,W-30V-20Cr的抗弯强度为437.13 MPa,比烧结纯钨增加了25%,HV硬度为6154 MPa;W-30V-20Cr合金具有较高的断裂韧性值,为15.51 MPa·m1/2。 相似文献
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Xianzhuo Jie Shuhua Liang Qingxiang Wang Xin Zhao Zhikang Fan Xianhui Wang 《Journal of Materials Engineering and Performance》2012,21(1):101-104
W-10Ti alloy was prepared by hot press sintering using W-TiH2 powders milled for 24 h under argon atmosphere. The effect of sintering temperature on the phase constituents and the microstructure
of the alloys was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron
microscopy (TEM). The microhardness of W-rich phase, electrical resistivity and impurity (C, O) contents of W-10Ti alloy were
determined. The results show that the amount of W-Ti solid solution, the microhardness of the W-rich solid solution and the
resistance of W-10Ti alloy increase with an increase of sintering temperature. At 1300 °C, W-10Ti alloy has the maximum microhardness
value of 333 HV0.05, the O content of 360 ppm and C content of 200 ppm. 相似文献
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93W-5.6Ni-l.4Fe tungsten heavy alloys with controlled microstructures were fabricated by mechanically alloying of elemental
powders of tungsten, nickel and iron by two different process routes. One was the full mechanical alloying of blended powders
with a composition of 93W-5.6Ni-l.4Fe, and the other was the partial mechanical alloying of blended powders with a composition
of 30W-56Ni-14Fe followed by blending with tungsten powders to form a final composition of 93W-5.6Ni-l.4Fe. The raw powders
were consolidated by die compaction followed by solid state sintering at 1300°C for 1 hour in a hydrogen atmosphere. The solid
state sintered tungsten heavy alloys were subsequently liquid phase sintered at 1445∼1485°C for 4-90 min. The two-step sintered
tungsten heavy alloy using mechanically alloyed 93W-5.6Ni-l.4Fe powders showed tungsten particles of about 6-15 μm much finer
than those of 40 um in a conventional liquid phase sintered tungsten heavy alloy. An inhomogeneous distribution of the solid
solution matrix phase was obtained in the two-step sintered tungsten heavy alloy using partially mechanically alloyed powders.
The two-step sintered tungsten heavy alloy using mechanically alloyed 93W-5.6Ni-l.4Fe powders showed larger elongation of
16% than that of 1% in the solid state sintered tungsten heavy alloy due to the increase in matrix volume fraction and decrease
in W/W contiguity. Dynamic torsional tests of the two-step sintered tungsten heavy alloys showed reduced shear strain at maximum
shear stress than did the sintered tungsten heavy alloys using the conventional liquid phase sintering. 相似文献
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LIU Dong-hua LIU Yong ZHAO Da-peng WANG Yan FANG Jing-hua WEN Yu-ren LIU Zu-ming 《中国有色金属学会会刊》2010,20(5):831-838
The microstructures and mechanical properties of an iron-based alloy (Fe-13Cr-3W-0.4Ti-0.25Y-0.30O) prepared by mechanical alloying were investigated with scanning electron microscope, optical microscope, X-ray diffractometer and hardness tester. The results show that the particle size does not decrease with milling time because serious welding occurs at 144 h. The density of the alloy sintered at 1 523 K is affected by the particle size of the powder. Finer particles lead to a high sintered density, while the bulk density by using particles milled for 144 h is as low as 70%. In the microstructures of the annealed alloy, large elongated particles and fine equiaxed grains can be detected. The elongated particle zone has a higher microhardness than the equiaxed grain area in the annealed alloys due to the larger residual strain and higher density of the precipitated phase. 相似文献
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A new tungsten heavy alloy, which is characterized by fine yttria stabilized cubic zirconia (c-ZrO2(Y)) particles dispersed in the alloy, was developed by an ion-level liquide-liquid (L-L) doping technique combined with mechanical alloying. The microstructure and mechanical properties of tungsten heavy alloy were investigated, and the formation process and role of zirconia were discussed. Results show the zirconium element transforms in an order of Zr4+ to Zr(WO4)2 or 2Zr(WO4)2 nH2O to m-ZrO2 in the preparation process of powders. Finally, the c-ZrO2(Y) particles with size of 200–1000 nm are obtained in tungsten heavy alloy during sintering at 1520 °C for 90 min. Most of c-ZrO2(Y) particles are distributed within tungsten grains, and some c-ZrO2(Y) particles tend to be dispersed at the interfaces of tungsten grains, while a small number of c-ZrO2(Y) particles are dispersed in γ(Fe, Ni, W) matrix. The compressive strength of new alloy is improved approximately 8.2% than that of 93 W-4.9Ni-2.1Fe. This attributes to c-ZrO2(Y), which refines tungsten grain, lowers W-W contiguity and strengthens tungsten and γ(Fe, Ni, W) grains. 相似文献
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X. Gong J.L. Fan F. DingM. Song B.Y. Huang 《International Journal of Refractory Metals and Hard Materials》2012,30(1):71-77
Tungsten heavy alloys (WHAs) with three different compositions (90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe and 95W-3.5Ni-1.5Fe, wt.%) were heavily deformed by one-pass rapid hot extrusion at 1100 °C with an extrusion speed of ~ 100 mm/s and an extrusion ratio of ~ 3.33:1. The influence of tungsten content on the microstructure and tensile fracture characteristics of the as-extruded alloys was investigated in detail. The results show that the tungsten particles in the as-extruded 95W have the largest shape factor compared to the as-extruded 90W and 93W alloys and this implies that the tungsten particles in the as-extruded 95W alloy were subjected to the heaviest plastic deformation. In addition, ultimate tensile strength (UTS) and hardness (HRC) are significantly improved after rapid hot extrusion. The as-extruded 95W alloy processes the highest strength (1455 MPa) and hardness (HRC40) but the lowest elongation (5%), followed by the as-extruded 93W (UTS1390MPa; HRC39; 7%) and 90W alloys (UTS1260MPa; HRC36; 10%). The fracture morphology shows the distinct fracture features between the as-sintered alloys and the as-extruded alloys. For the as-sintered alloys, the fracture modes are various while transgranular cleavage of tungsten particles is the main characteristic in the as-extruded alloy. Meanwhile, the fracture modes of the three as-extruded alloys vary slightly with the tungsten content. TEM bright field images indicate that many lath-like subgrains with the width of 150-500 nm are present in the three as-extruded alloys, particularly in the as-extruded 93W and 95W alloys. Furthermore, the dislocations are absent in the γ-(Ni, Fe) phase. This means that dynamic recovery-recrystallization process took place during rapid hot extrusion. 相似文献
20.
采用激光熔覆技术在27SiMn钢基体表面成功制备了不同La_2O_3含量的铁基JG-8合金复合涂层,系统地研究了添加La_2O_3对铁基JG-8合金复合涂层组织及性能的影响。利用X射线衍射仪(XRD)和配有能谱仪(EDS)的扫描电子显微镜(SEM)对铁基JG-8合金复合涂层的物相结构和显微组织进行分析测试,通过显微硬度仪和摩擦磨损试验机对铁基JG-8合金复合涂层的硬度以及摩擦学性能进行分析评估。结果表明,La_2O_3的添加可有效细化组织,使晶粒由原本的柱状晶转变为细小的胞状结构。铁基JG-8合金复合涂层的硬度随着La_2O_3含量的增加呈现先增大后减小的趋势,其中0.8%La_2O_3(质量分数)铁基JG-8合金复合涂层的硬度(HV0.3)(5327MPa)最高,与未添加La_2O_3的铁基JG-8涂层相比,0.8%La_2O_3铁基JG-8合金复合涂层的硬度提升了19.4%。在摩擦磨损过程中未添加La_2O_3的铁基JG-8涂层主要磨损机制为粘着磨损和疲劳磨损,0.8%La_2O_3铁基JG-8合金复合涂层的主要磨损机制为磨粒磨损,0.8%La_2O_3铁基JG-8合金复合涂层的体积磨损量最低,为27SiMn钢基体的22.9%。 相似文献