材料期刊网

CERIUM-INDUCED GRAIN BOUNDARY STRENGTHENING OF Ni_3Al ALLOYS

Z.X. Yuan , S.H. Song , T.H. X.i , X.J. Zhangand Z.S. Yu(Department of Material , Wuhan Ye in University of Science and Technology , Wuhan 430081 , China)(Department of Materials Physics , University of Science and Technology Beijing , Beijing 100083 , China)

金属学报(英文版)

The infiuence of cerium on grnin boundaries of polycrpstalline N3Al alloys has beenstudied. The ja6mcability of a Ce-doped N3Al alloy strongly depends on the certumcontent. The alloy exhibits very poor fabrica6ility and cannot be fabrtcated into goodsheet8 by cold rolling when the concentmtion of cerium is <0. 0088wt% or>0.044wt%.A 0.011wt%Ce-doped N3Al alloy exhibits relatively good fabricability and may be fab-ricated into useful sheets by repeated cold rolling with 1OOa C annealing. The ductilityof the alloy strongly depends on the cerium distribution. Wthout the grain boundaryprecipitation of a second phase containing cer1um) the higher the segmpation level ofcerzum, the 6ettcr the tensile properties of the alloys, and in turn the more enhancedthe grain boundary cohesion.

关键词: segregation , null , null , null , null

First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X = H, D, and T) system

Journal of Alloys and Compounds

As hydrogen, deuterium and tritium storage materials, a series of investigations of mechanical and thermal properties of titanium hydrides, deuterides and tritides have been performed, however, very limited theoretical studies of thermodynamic properties for them can be found. Based on density-functional theory (DFT) and density-functional perturbation theory (DFPT) we have discussed systematically the hydrogen isotope effects on the thermodynamic properties of TiX2 (X = H, D, and T) system. Our calculations indicate that for evaluating accurately their physical properties at absolute zero temperature, such as the equilibrium lattice constants, bulk modulus, and heat of formation, the zero-point energy correction must be taken into account. By performing the phonon calculation within quasiharmonic approximation (QHA), we obtain their vibrational free energies, vibrational entropies, and temperature dependence of specific heat, thermal expansion, and bulk modulus. Those results demonstrate that comparing with TiH2, TiT2 and TiD2 are more stable and the zero-point effects play an important role in their thermal expansion. The increase in the force constant between Ti and H causes the higher value of specific heat of TiH2 during the phase transition from FCC to FCT. In addition, comparing with available experimental values, we can conclude that QHA is feasible for describing the thermal properties of TiX2. (C) 2006 Elsevier B.V. All rights reserved.

关键词: isotope effects;thermodynamic properties;density-functional;perturbation theory;quasiharmonic approximation;functional perturbation-theory;neutron spectroscopy;thermal-properties;titanium;hydrogen;dependence;expansion;constants;palladium;hydrides

08X18H10T多轴低周疲劳变形显微结构的研究

丰崇友 , 刘向东 , 李洪波

兵器材料科学与工程 doi:10.3969/j.issn.1004-244X.2007.03.011

对08X18H10T不锈钢进行单轴及多轴非比例循环加载低周疲劳试验及其微结构的观察,分析单轴及多轴非比例加载低周疲劳特性及其变形微观机理,结果表明:多轴非比例加载过程中,奥氏体不锈钢08X18H10T产生明显的非比例附加强化;在应变幅值较大时,塑性变形不仅通过滑移方式进行,还有孪生变形方式,微观形貌由平面状滑移向波纹状滑移转化.

关键词: 08X18H10T不锈钢 , 非比例循环载荷 , 附加强化 , 位错 , 孪晶

10X11H23T3MP-BД不锈钢材料的耐蚀性能

钱建刚 , 李荻 , 郭宝兰

腐蚀学报（英文）

通过高温抗氧化、盐雾腐蚀和应力腐蚀试验研究了10X11H23T3MP-BД不锈钢材料在使用状态（时效态）时的耐蚀性能.结果表明：该不锈钢材料在试验温度500℃和600℃时的空气介质中为完全抗氧化，在700℃和800℃时的空气介质中为抗氧化；500℃和600℃下的氧化动力学曲线符合对数规律，700℃和800℃下的氧化动力学曲线则符合直线规律；在35%NaCl中性盐雾介质中的抗腐蚀性能优良；在35%NaCl溶液中对应力腐蚀断裂存在一定的敏感性.

关键词: 抗氧化性 , null , null

10X11H23T3MP-BД不锈钢材料的耐蚀性能

钱建刚 , 李荻 , 郭宝兰

腐蚀学报（英文） doi:10.3969/j.issn.1002-6495.2004.06.006

通过高温抗氧化、盐雾腐蚀和应力腐蚀试验研究了10X11H23T3MP-BД不锈钢材料在使用状态(时效态)时的耐蚀性能.结果表明:该不锈钢材料在试验温度500℃和600℃时的空气介质中为完全抗氧化,在700℃和800℃时的空气介质中为抗氧化;500℃和600℃下的氧化动力学曲线符合对数规律,700℃和800℃下的氧化动力学曲线则符合直线规律;在3.5%NaCl中性盐雾介质中的抗腐蚀性能优良;在3.5%NaCl溶液中对应力腐蚀断裂存在一定的敏感性.

关键词: 抗氧化性 , 盐雾试验 , 应力腐蚀 , 不锈钢

钛合金BT9和08X18H10T不锈钢多轴低周疲劳损伤的微观机理

于海生 , 丰崇友 , 王兴国 , 舒卡耶夫 谢.尼.

材料开发与应用 doi:10.3969/j.issn.1003-1545.2006.01.001

研究了钛合金BT9和08X18H10T不锈钢在比例和非比例载荷下的低周疲劳特性,非比例载荷下钛合金BT9附加强化程度很小,08X18H10T不锈钢则产生了明显的附加强化,而二者的疲劳寿命均降低明显.采用透射电镜(TEM)对钛合金BT9及08X18H10T不锈钢的疲劳位错亚结构进行了对比分析,结果表明:非比例载荷下,钛合金BT9中局部高密度位错,以及08X18H10T不锈钢面塑性变形方式从平面状滑移向波纹状滑移转化,是其低周疲劳损伤程度加剧及寿命降低的主要原因.

关键词: 低周疲劳 , 钛合金BT9 , 08X18H10T不锈钢 , 附加强化 , 亚结构

核电站用核级08X18H10T不锈钢管的国产化

郑越 , 马可腾 , 崔岚 , 张跃 , 马小军

机械工程材料

为对核电站原始设计用核级08X18H10T奥氏体不锈钢管采用国产TP321钢管进行替代,分析了国产TP321钢的化学成分、制造工艺以及热处理工艺对TP321钢管室温和350℃拉伸性能、显微组织、晶粒度以及抗晶间腐蚀性能的影响,确定了合适的成分与工艺.结果表明:调整后工艺是在TP321钢制造过程中增大坯料尺寸并在原有工艺的基础上增加一道冷轧、中间热处理和一道冷拔,然后在1 100℃固溶保温11min;工艺调整后制备的TP321钢管室温抗拉强度可由原有工艺的540 MPa提高到556MPa,350℃屈服强度由170 MPa提高到250 MPa,晶粒度达4.5级;通过控制TP321钢的化学成分使国产TP321钢管既能满足ASME的规定,同时也能达到对08X18H10T钢力学性能的要求,实现此不锈钢管的国产化.

关键词: TP321钢 , 化学成分 , 制造工艺 , 力学性能

T6I6时效对6061铝合金拉伸及晶间腐蚀性能的影响

李海潘道召王芝秀郑子樵

金属学报 doi:10.3724/SP.J.1037.2009.00570

对T6I6时效处理的6061铝合金的拉伸性能、晶间腐蚀性能和电导率进行了测试, 并采用OM和TEM对其组织进行了观察. 结果表明, 6061铝合金经180℃×8 h T6峰值时效后, 虽然强度较高, 但有严重晶间腐蚀倾向;T6I6预时效时间对拉伸性能影响不大, 但中断时效温度和时间对其影响显著.由于较高的中断时效温度和较长的中断时间能获得高密度的晶内析出相和呈球状不连续分布的晶界析出相, 因此, T6I6时效处理后的6061铝合金不仅能保持较高强度, 同时还能显著提高晶间腐蚀抗力. 经180 ℃×2 h+150 ℃×2160 h+180 ℃×8 h T6I6时效, 合金抗拉强度和屈服强度分别为348.5和326.9 MPa, 相对于T6状态, 仅分别下降了2.1%和1.4%,腐蚀类型由T6状态的晶间腐蚀转变为均匀腐蚀, 腐蚀深度约为30 μm.

关键词: 6061铝合金 , T6I6 temper , tensile properties , intergranular corrosion

Theoretical investigations of the spin hamiltonian parameters for the tetragonal Cu2+ centers in NH4X (X = Cl, Br, I)

International Journal of Modern Physics B

The spin Hamiltonian (SH) parameters g factors g parallel to, g perpendicular to and the hyperfine structure constants A parallel to and A perpendicular to for the tetragonal Cu2+ centers (i.e., [CUX4(H2O)(2)] clusters) in NH4X (X = Cl, Br, I) are theoretically investigated by means of the diagonalization procedure of complete (10 x 10) energy matrix (DPCEM) for a 3d(9) ion in tetragonal symmetry. The crystal-field parameters in the energy matrix are determined from the superposition model. The calculated SH parameters are in reasonable agreement with the experimental data.

关键词: crystal fields and spin hamiltonians;electron paramagnetic resonance;Cu2+;NH4X (X = Cl, Br, I);electron-paramagnetic-res;atomic screening constants;superposition;model;single-crystals;phase-diagram;scf functions;high-pressure;complexes;ions

T6和T6I4时效工艺对7055铝合金切削加工性能的影响

刘文辉 , 杨迅雷 , 张平 , 陈宇强 , 唐思文

材料热处理学报

采用测力仪,表面粗糙度仪、三维表面轮廓仪、透射电镜等对T6和T6I4态7055铝合金的切削加工性能进行研究,分析了时效工艺对7055铝合金加工性能的影响.结果表明,由于T6I4态7055铝合金的析出更加细小密集,T6I4态7055铝合金硬度和强度高于T6态,T6I4态切削表层显微硬度高于T6态;在相同切削条件下,T6I4态的切削力比T6态的切削力小,T6I4态表面粗糙度较T6态低,具有较好的加工质量;在切削热的影响下T6I4态比T6态更易发生回归,因此T6I4态7055铝合金的切削力小于T6态.

关键词: 7055铝合金 , 加工性能 , 时效处理 , 粗糙度