等离子喷涂Gd_2Zr_2O_7-SrZrO_3复合陶瓷涂层的微观结构和性能

通过固相反应法合成了Gd_2Zr_2O_7-SrZrO_3 (GZSZ,Gd_2Zr_2O_7:SrZrO_3=7:3)复合陶瓷粉末,并采用喷雾造粒法和大气等离子喷涂法分别制备了适合等离子喷涂使用的相应喷涂粉末及涂层。使用X射线衍射、扫描电子显微镜对粉末和涂层的相组成、显微结构进行分析。借助激光热导仪、高温热膨胀仪对涂层的热扩散系数和热膨胀系数、烧结系数进行了表征。结果表明,制备的GZSZ复合陶瓷粉末和涂层都由Gd_2Zr_2O_7和SrZrO_3两相组成,粉末中的Gd_2Zr_2O_7为烧绿石结构,而涂层中的Gd_2Zr_2O_7为萤石结构,SrZrO_3都为钙钛矿结构。制备态GZSZ涂层的孔隙率为～14%。GZSZ涂层1400℃热处理5 h后的热膨胀系数为(9.8～11.2)×10~(-6) K~(-1)。制备态GZSZ涂层的热导率为～0.8 W·m~(-1)·K~(-1),与制备态SrZrO_3涂层的热导率～1.0 W·m~(-1)·K~(-1)相比降低～20%。1400℃热处理360 h后GZSZ涂层的热导率增加到～1.5 W·m~(-1).K~(-1)。综上表明,GZSZ涂层是一种很有前景的复合陶瓷热障涂层材料。     

高温热循环对不同结构YSZ涂层隔热性能的影响

研究了高温热循环对不同结构YSZ涂层隔热性能的影响。结果表明:相对于亚微米YSZ涂层的细密柱晶结构,纳米YSZ涂层内有明显的层状结构和未熔颗粒存在,这利于降低涂层的热导率和提高涂层的隔热性能。在1100℃时,喷涂态的纳米涂层的热导率低于亚微米涂层,其中,SAPS(超音速等离子喷涂)的纳米涂层的热导率最低(1.41W·m~(-1)·K~(-1))。经过7次热循环后,APS(大气等离子喷涂)微米涂层的热导率升至最高(4.91 W·m-1·K-1),而SAPS(超音速等离子喷涂)的纳米涂涂层热导率则降低至0.92 W·m~(-1)·K~(-1)。热循环初期,APS涂层隔热效果均高于SAPS涂层;热循环过程中,SAPS涂层的隔热温度升高,而APS涂层的隔热温度则下降。涂层的热导率与隔热变化趋势保持一致。     

Gd2 O3 -Yb2 O3 -Y2 O3 -ZrO2 热障涂层材料的热物理性能

目的通过多元稀土氧化物掺杂改性YSZ,提高传统热障涂层的性能。方法使用化学共沉淀法制备不同掺杂量的Gd2O3-Yb2O3-Y2O3-Zr O2(GYYZO)材料,并分别使用冷等静压-烧结和等离子喷涂工艺制备块材和涂层。通过测试块材的热导率和热膨胀系数,分析评价材料的热物理性能。对高温退火处理后的涂层进行X射线衍射分析,评价不同成分涂层的高温相稳定性。结果氧化锆基材料的热导率和热膨胀系数随总掺杂量升高而降低。氧化锆中稀土氧化物总掺杂量为5.5%~9.84%(摩尔分数)时,在1000℃下的热导率为1.25~1.56 W/(m·K),相对8YSZ材料下降了22%~37.5%;在200~1300℃的热膨胀系数为(10~11.1)×10-6/K,与传统8YSZ材料相当。在1400℃长时间退火处理后,低掺杂量GYYZO涂层中的单斜相含量明显低于8YSZ涂层。结论多元稀土氧化物掺杂改性氧化锆材料具有良好的高温相稳定性、低热导率和适当的热膨胀系数,可以作为高性能热障涂层的备选材料。     

TiO2掺杂SmTaO4陶瓷热物理性能研究

热障涂层是燃气轮机高温部件保护的重要材料之一,SmTaO4陶瓷具有优异的高温相稳定性和力学性能,有望成为新型热障涂层材料。本研究采用固相法制备TiO2掺杂SmTaO4陶瓷,研究结果表明：掺杂TiO2未改变SmTaO4陶瓷晶体结构,样品均为单斜相,掺杂2% mol TiO2的SmTaO4陶瓷烧结过程中出现的第二相为Sm0.33TaO3;随着TiO2含量增加,SmTaO4陶瓷的热导率先下降后上升,当TiO2掺杂含量为2%时,热导率最低为1.42W?m?1?K?1,低于SmTaO4（1.59W?m-1?K-1,900℃）,与7-8YSZ相比（2.1~2.7 W?m?1?K?1,100~900℃）下降了近30%。掺杂2%TiO2的SmTaO4陶瓷热膨胀性系数最大值为10.8×10-6K-1,大于YSZ（~10.0×10-6K-1）和SmTaO4（9.62×10-6K-1,1200℃）,与纯SmTaO4相比,TiO2掺杂提高了SmTaO4陶瓷的热膨胀系数。因此,TiO2掺杂SmTaO4陶瓷有望作为新型热障涂层材料使用。     

新型锆酸盐基热障涂层材料的研究进展

简要回顾了传统7±1 %Y_2O_3稳定的ZrO_2(YSZ)热障涂层的研究现状,指出YSZ涂层在高温热循环下存在着相变,抗烧结能力差等缺点.鉴于新型稀土锆酸盐系列由于具有热导率低、抗烧结能力强等优点而被认为有望作为新一代热障涂层候选材料,重点概述了目前国内外在这种热障涂层材料的陶瓷块体制备及涂层材料方面的研究现状,并进一步探讨了未来新型稀土锆酸盐基热障涂层的发展方向.     

热压烧结制备Cu/FeCoCr复合材料的显微组织及热物理性能（英文）

利用相图计算的CALPHAD方法和超音雾化制粉技术,在CuFeCoCr体系中设计并制备了一系列微米级复合粉体。通过热压烧结方法在烧结温度为950℃,烧结压力为45 MPa的工艺条件下成功获得块体复合材料。研究了块体复合材料中Cu含量对显微组织,热导率,热膨胀系数以及显微硬度的影响。结果表明:CuFeCoCr块体复合材料均由fcc富铜相和fcc富铁钴铬相组成。该系列复合材料经600℃时效处理8 h后,其热膨胀系数变化范围为5.83×10~(-6)～10.61×10~(-6) K~(-1),热导率变化范围为42.17～107.53 W·m~(-1)·K~(-1)。其中Cu_(55)(Fe_(0.37)Cr_(0.09)Co_(0.54))_(45)复合材料表现出良好的综合性能,即其热膨胀系数和热导率分别为9.08×10~(-6)K~(-1)和91.09 W·m~(-1)·K~(-1),与电子封装半导体材料的热膨胀系数相匹配。     

爆炸喷涂空心球形氧化锆热障涂层的抗热冲击性能

在镍基高温合金基体DSM11上制备双层结构的热障涂层．粘结底层采用电弧离子镀技术制备的NiCoCrAlY涂层，陶瓷顶层采用爆炸喷涂技术制备的Y2O3部分稳定的ZrO2(YSZ)陶瓷涂层，粉末采用普通实心YSZ粉、空心球形YSZ粉对制备的热障涂层进行热导率测定和热冲击性能实验．结果表明：爆炸喷涂制备的空心YSZ陶瓷层涂层具有低的热导率和良好的抗热冲击性能。     

深冷处理对TC6钛合金热导率和热膨胀系数的影响

对TC6钛合金进行深冷处理,通过对比深冷处理前后合金在25～600℃范围内的热导率和热膨胀系数的变化,探讨了深冷处理对TC6钛合金热导率和热膨胀系数的影响。结果表明:随着温度升高,经深冷处理合金的热导率先小于后大于未经深冷处理合金的热导率,而热膨胀系数则先略大于后小于未经深冷处理合金的热膨胀系数。600℃时,经深冷处理合金的热导率和热膨胀系数分别为7.95 W·m~(-1)·K~(-1)和1.17×10~(-5)·℃~(-1),较相同温度下未经深冷处理的分别增大和减小了14.88%(1.03 W.m~(-1)·K~(-1))和1.62%(0.19×10~(-6)·℃~(-1))。     

大气等离子喷涂热障涂层CMAS防护层成分及厚度优化

目的优化热障涂层(TBCs)CMAS(CaO-MgO-Al_2O_3-SiO_2)阻抗层的成分和厚度,使其能有效阻抗CMAS沉积物的腐蚀,并同时与热障涂层有较高的结合力。方法首先利用多孔无压烧结陶瓷块体研究了不同含量Al_2O_3和8YSZ(8wt.%氧化钇稳定氧化锆)均匀混合后在高温(1250℃)条件下对CMAS沉积物的防护作用。采用扫描电子显微镜(SEM)、能谱仪(EDS)以及X射线衍射(XRD)仪,分析研究了CMAS腐蚀层的显微结构、腐蚀深度及反应产物。其次,基于最优成分,利用大气等离子喷涂(APS)制备了具有8YSZ/Al_2O_3陶瓷层的热障涂层。对CMAS腐蚀厚度进行分析测量,提出CMAS阻抗层的厚度。结果 Al_2O_3的添加可以有效地阻碍CMAS的渗入,并且Al_2O_3含量越多,防护效果越好。但是CMAS的渗入深度和氧化铝的添加量呈非线性关系。结合TBC陶瓷层的热学性能和力学性能的要求,本实验中最佳的TBCs复合陶瓷层组分为70wt%8YSZ+30wt%Al_2O_3。基于实验结果,提出YSZ/Al_2O_3复合陶瓷层(50μm)-YSZ陶瓷层(150μm)的双层TBC陶瓷层结构,并综合计算出复合陶瓷层的热膨胀系数为9.93×10-6℃-1以及双层TBC陶瓷层的热导率为2.4 W/(m·K)。最后对Al_2O_3减缓CMAS腐蚀的机理进行了量化分析。结论 YSZ/Al_2O_3复合阻抗层的最优成分为70wt%8YSZ+30wt%Al_2O_3,厚度为50μm,能有效阻碍高温下CMAS腐蚀。     

(Gd0.8Ca0.2)2Ce2O6.6陶瓷的制备及热导率

以Gd2O3、CeO2和CaO为原料,采用固相反应法制备(Gd0.8Ca0.2)2Ce2O6.6陶瓷材料。用X射线衍射(XRD)技术和扫描电镜(SEM)研究样品的相组成和微观组织,用激光脉冲法测试样品的热扩散系数。结果表明,所制备的样品具有单一的萤石结构,组织致密且晶界清晰,其在800℃的热导率仅为YSZ陶瓷的89%,较低热导率表明该材料有潜力用作新型热障涂层用陶瓷材料。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

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.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

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.     

Information for Contributors

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