Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10.0)Be_(22.5)大块非晶合金的切屑和切削力试验(英文)

为了解非晶合金的切削机理,对大块非晶合金Zr41.2Ti13.8Cu12.5Ni10.0Be22.5进行了不同切削深度的切削实验,然后用扫描电镜、X光衍射仪和测力系统对切屑形态和切削力进行观察和测量。实验结果表明:Zr基非晶合金在受拉的时候,比全脆性材料有更好的塑性表现,其切屑形态独特且具有塑性剪切带特征;主切削力Fz随切削深度的增加而增长,但Fx和Fy则几乎没有变化。     

石墨烯对La_(0.94)Mg_(0.06)Ni_(3.49)Co_(0.73)Mn_(0.12)Al_(0.20)储氢合金电化学性能的影响

为了提高La_(0.94)Mg_(0.06)Ni_(3.49)Co_(0.73)Mn_(0.12)Al_(0.20)储氢合金的电化学性能,利用石墨烯与储氢合金研磨混合来对其进行表面改性处理。采用X射线粉末衍射仪(XRD)和扫描电子显微镜(SEM)分析合金的相结构和表面形貌。结果表明:添加石墨烯后合金的相结构并没有发生改变,石墨烯包覆在了合金的表面,增大了合金的比表面积,提高了合金的电化学性能。当添加质量分数为5%的石墨烯时,电极的最大放电容量可达到380.6mAh/g,容量保持率S50从69.5%提高到71.1%。添加石墨烯后,交换电流密度、极限电流密度和腐蚀电位均变大、电化学反应阻抗降低,说明电极的动力学性能得到改善。     

La_(0.4)Sr_(0.6)Co_(0.2)Fe_(0.7)Nb_(0.1)O_(3-δ)电极应用于YSZ基对称SOFC性能研究

采用固相法合成了钙钛矿型氧化物La_(0.4)Sr_(0.6)Co_(0.2)Fe_(0.7)Nb_(0.1)O_(3-δ)(LSCFN),并采用流延-丝印法制备了以8 mol%Y_2O_3稳定Zr O_2(YSZ)为电解质、Gd_(0.1)Ce_(0.9)O_(2-δ)(GDC)为隔离层、LSCFN同时为阴极和阳极的对称固体氧化物燃料电池。利用X射线衍射对电极材料进行了物相及化学相容性分析,用扫描电镜表征了对称电池的微观形貌。分别以湿H_2(3%H_2O)和湿CH_4(3%H_2O)为燃料气,空气为氧化气测试了单电池的电化学性能,并在850℃湿CH_4下进行了电池的稳定性测试。结果表明:LSCFN与GDC具有良好的化学相容性。以湿H_2和湿CH_4为燃料气的单电池在850℃时最大功率密度分别为254和105 m W/cm~2。在100 h的CH_4稳定性测试中性能无明显衰减,具有良好的稳定性。     

非晶合金Fe_(80-x)Cu_xSi_5B_(15)和(Fe_(1-y)Co_y)_(82)Cu_(0.4)Si_(4.4)B_(13.2)的晶化行为

用X射线衍射、吸收和内转换电子发射Mossbauer谱技术,研究了Fe_(80-x)Cu_xSi_5B_(15)和(Fe_(1-y)Co_y)_(82)Cu_(0.4)Si_(4.4)B_(13.2)两系列非晶合金的晶化行为.单辊急冷法制备的非晶带,晶化首先从贴辊面开始,晶化产物为α-Fe相.在Fe_(80)Si_5B_(15)非晶合金中以少量Cu替代Fe可以提高晶化温度.我们的结果表明,过渡金属的含量超过80at.-%,如增加到82at.-%,晶化温度就明显降低.所研究两系列含Si的铁基非晶合金在400—450℃范围内退火2h,都出现α-Fe,Fe_3B和Fe_2B三种晶态相共存状态.退火温度再升高,亚稳相Fe_3B逐渐转变为Fe_2B和α-Fe.     

磁制冷合金Mn_(1.2)Fe_(0.8)P_(0.76)Ge_(0.24)的相变过程研究

采用放电等离子烧结和机械合金化技术制备了组织致密的Mn1.2Fe0.8P0.76Ge0.24磁制冷合金,并对其相变过程进行了研究。结果表明,随着温度的降低和磁场强度的增加,合金均由顺磁相转变为铁磁相,对应熵变值呈增大趋势。     

盐酸液中钇(Ⅲ)和铕(Ⅲ)的P_(507)溶剂萃取平衡分析(英文)

为了精确预测非理想条件下稀土金属溶剂萃取的平衡分配比,研究了溶于ShellsolD70中的P507溶剂对盐酸液中钇(Ⅲ)和铕(Ⅲ)的萃取平衡,建立化学基模型,并通过非线性最小二乘法确定萃取平衡常数。所建模型涉及了在低酸度区的离子交换反应和高酸度区的溶剂化萃取反应;模型还考虑了稀土金属与Cl-的配位反应,并用萃取剂的有效浓度代替[(HR)2],进而分别对水相和有机相(HR)2的非理想性加以修正。对稀土单元体系,在较宽的初始浓度范围内(稀土浓度最高至0.1mol/L,盐酸浓度0.07-3.00mol/L,萃取剂浓度0.25-1.00mol/L),由模型计算的稀土分配比与实验测得的数据吻合良好,验证了模型的有效性。对于稀土二元体系,该模型能以良好的精度对平衡分配比进行工程预测。     

Mn_(1.2)Fe_(0.8)P_(0.74)Ge_(0.26-x)Se_x化合物磁热性能研究

利用机械合金化(MA)结合放电等离子烧结(SPS)技术,成功制备了Mn1.2Fe0.8P0.74Ge0.26-xSex(x=0,0.005,0.01,0.015,0.02,0.03)化合物,并采用XRD,DSC,振动样品磁强计(VSM)和磁热效应直接测量仪等手段对其晶体结构、相变过程以及磁热性能进行了研究.结果表明:该系化合物均具有六方Fe2P结构.随着Se含量的增加,晶格常数a和c都发生了明显的变化,c/a先减小,然后保持不变,最后又增大;且c/a的值与化合物的Curie温度Tc成一定对应关系,c/a减小会升高Tc,反之则降低Tc.外加磁场和温度的变化都能引起化合物产生一级磁热相变,即顺磁相(PM)?铁磁相(FM).少量Se对Ge的置换(x≤0.015)能够提高材料的磁热性能,使该系化合物的Tc升高,转变温区?Tcoex变窄,绝热温变?Tad增大;而热滞?Thys和熵变?SDSC基本不变.当x=0.01时,化合物的磁热性能最好,与x=0化合物相比,Tc升高了5.6 K,?Tcoex降低了10.6%,?Tad增加了10%,当Se含量继续增加时,化合物的磁热性能有所下降.     

Mo对铁基块体非晶合金Fe_(71.2-x)C_(7.0)Si_(3.3)B_(5.5)P_(8.7)Cr_(2.3)Al_(2.0)Mo_x腐蚀性能的影响

系统研究了3.5%NaCl和1N HCl两种溶液中Mo对工业原材料制备的块体非晶合金Fe71.2-xC7.0Si3.3B5.5P8.7Cr2.3Al2.0Mox的抗腐蚀性能的影响,结果发现随着Mo含量的增加,两种溶液中均表现出抗腐蚀性能的增强。其中Fe64.7C7.0Si3.3B5.5P8.7Cr2.3Al2.0Mo6.5块体非晶合金因为其最低的钝化电流、最高的临界钝化电位、最低的腐蚀速率而表现出最高的抗腐蚀能力。抗腐蚀性能随着Mo含量增加而增强,其可能的原因包括:化学和结构均匀单相固溶体的形成;样品表面形成了富Cr的钝化膜,而Mo则在钝化过程中进一步阻止了Cr的溶解;MoO3及其他的复合钝化膜的形成以及Mo的添加在Cl-离子介质中所引起的抗点蚀能力的增强。     

退火对(Fe_(50)Co_(25)Si_(10)B_(15))_(70)Cu_(30)非晶薄带磁性的影响

研究了(Fe50Co25Si10B15)70Cu30和Fe50Co25Si10B15非晶薄带辊面和自由面的相组成、微观结构以及磁性能。结果表明,(Fe50Co25Si10B15)70Cu30非晶薄带形成了独特的双层金属玻璃复合结构。并且,(Fe50Co25Si10B15)70Cu30非晶薄带的单辊面是含有微米级晶体Cu颗粒的以Fe、Co为基底的非晶层;而Fe50Co25Si10B15非晶薄带为非晶态。同时,(Fe50Co25Si10B15)70Cu30非晶薄带退火后软磁性能有所恶化。     

热处理对Ti_(35)Zr_(30)Be_(27.5)Cu_(7.5)非晶合金压缩性能的影响

利用铜模铸造法获得了直径为2 mm的Ti35Zr30Be27.5Cu7.5块体非晶合金。采用X射线衍射(XRD)、扫描电镜(SEM)、差氏扫描量热仪(DSC)及压缩试验等方法研究了非晶合金的相结构、显微组织和热稳定性,以及热处理对其压缩强度及塑性的影响。结果表明:在553和583 K温度下分别保温5 h后,实验合金仍保持为非晶态;在613 K保温1 h后,有晶化相出现。Ti35Zr30Be27.5 Cu7.5非晶合金在583 K下保温1 h后其塑性变形量达到了6.57%,较热处理前提高了1倍,且保持了热处理前的强度,屈服强度和抗压强度分别为1921 MPa,2169 MPa。随着热处理温度的提高,非晶相含量减少,合金断裂强度、塑性变形量随之降低;同时合金断裂方式由韧性断裂转变为脆性断裂。     

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.     

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.     

Microstructure and Mechanical Properties of X80 Pipeline Steel Joints by Friction Stir Welding Under Various Cooling Conditions

X80 pipeline steel plates were friction stir welded(FSW) under air, water, liquid CO_2 + water, and liquid CO_2 cooling conditions, producing defect-free welds. The microstructural evolution and mechanical properties of these FSW joints were studied. Coarse granular bainite was observed in the nugget zone(NZ) under air cooling, and lath bainite and lath martensite increased signifi cantly as the cooling medium temperature reduced. In particular, under the liquid CO_2 cooling condition, a dual phase structure of lath martensite and fi ne ferrite appeared in the NZ. Compared to the case under air cooling, a strong shear texture was identifi ed in the NZs under other rapid cooling conditions, because the partial deformation at elevated temperature was retained through higher cooling rates. Under liquid CO_2 cooling, the highest transverse tensile strength and elongation of the joint reached 92% and 82% of those of the basal metal(BM), respectively, due to the weak tempering softening. A maximum impact energy of up to 93% of that of the BM was obtained in the NZ under liquid CO_2 cooling, which was attributed to the operation of the dual phase of lath martensite and fi ne ferrite.     

INDUSTRY NEWS

China Securities News reported on March 21, 2014： Guangdong Hongtu Wuhan Die Casting Co., Ltd. （Wuhan Hongtu）, a wholly owned subsidiary of Guangdong Hongtu Technology （Holdings） Co., Ltd., held a groundbreaking ceremony recently. With the registered capital of 50 million Yuan, Wuhan Hongtu has a total land area of 100,000 square meters and a plant construction area of 72,000 square meters. It is expected to have a production capacity of about 30,000 tonnes of aluminum castings annually after it is put into production.     

Microstructure,Mechanical Properties and Corrosion Behavior of Extruded Mg–Zn–Ag Alloys with Single-Phase Structure

Mg–Zn–Ag alloys have been extensively studied in recent years for potential biodegradable implants due to their unique mechanical properties,biodegradability and biocompatibility.In the present study,Mg–3Zn-x Ag(wt%,x=0.2,0.5 and0.8)alloys with single-phase crystal structure were prepared by backward extrusion at 340°C.The addition of Ag element into Mg–3Zn slightly influences the ultimate tensile strength and microstructure,but the elongation firstly increases from12%to 19.8%and then decreases from 19.8%to 9.9%with the increment of Ag concentration.The tensile yield strength,ultimate tensile strength and elongation of Mg–3Zn–0.2Ag alloy reach up to 142,234 MPa and 19.8%,respectively,which are the best mechanical performance of Mg–Zn–Ag alloys in the present work.The extruded Mg–3Zn–0.2Ag alloy also possesses the best corrosion behavior with the corresponding corrosion rate of 3.2 mm/year in immersion test,which could be explained by the single-phase and uniformly distributed grain structure,and the fewer twinning.     

Growth Morphologies of a Binary Alloy with Low Anisotropy in Directional Solidification

Two new classes of growth morphologies, called doublons and seaweed, were simulated using a phase-field method. The evolution of doublon and seaweed morphologies was obtained in directional solidification. The influence of orientation and velocity on the growth morphology was investigated. It was indicated that doublons preferred growing with its crystallographic axis aligned with the heat flow direction. Seaweed, on the other hand, could be obtained by tilting the crystalline axis to 45°. Stable doublons could only exist in a range of velocity regime. Beyond this regime the patterns formed would be unstable. The simulation results agreed with the reported experimental results qualitatively.