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EFFECT OF Cr ADDITION ON MICROSTRVCTURES AND MECHANICAL PROPERLIES OF β-NiAl ALLOYS

W.H. Tian , S.L. Hu and M. Nemoto(1) Department of Materials Physics , University of Science and Technology Beijing , Beijing 100083 , China 2) Department of Materials Forming , University of Science and Technology Beijing , Beijing 100083 , China 3) Department of Materials Science and Engineering , Faculty of Engineering , Kyushu University , Fukuoka 812 , Japan)Manuscript received in revised form 12 October 1998

金属学报(英文版)

The effect of Cr addition on the microstructures and mechanical properties of NiAl inermetallic alloys containing 4 to 8 mol% Cr has been characterized. It is shown that Cr is not only an efficient soild solution strengthener in NiAl, it is also an efficient precipitation Strengthener by fine dispersion of α-Cr particles. Transmission electron microscope observations have revealed that fine spherical particles of α-Cr appeared homogeneously in the NiAl matrix by aging at temperatures around 1073K after solution annealing at 1563K. The aging behavior was investigated by microhardness measurements and the temperature dependence of the yield stress of NiAl containing α-Cr particles was investigated by compression tests over the tempemture range from 298 to 1173K. NiAl alloys happened appreciably by the precipitation of α-Cr particles.Dislocations bypass the particles during deformation and typical Orowan loops were observed surrounding the α-Cr particles after deformation. Although the dispersion Of α-Cr particles increases the yield strength of NiAl at intermediate temperutre, the strength decreases appreciably at higher temperatures.

关键词: NiAl , null , null , null , null

MICROSTRUCTURES AND MECHANICAL PROPERTIES OF β-NiA1 CONTAINING α-Fe PRECIPITATES

W.H. Tian , A.L. Fan and M. Nemoto (Department of Materials Physics and Chemistry , University of Science and Technology Beijing , Beijing 100083 , China , Sasebo National College of Technology , Okishin 1-1 , Sasebo 857-1193 , Japan)

金属学报(英文版)

The microstructures of B2-ordered NiA1 containing α-Fe precipitates have been investigated in terms of transmission electron microscopy. Fine precipitation of α-Fe (bcc structure) occurs in NiA1 by aging around 973K. The aging behavior was investigated by microhandness measurements and the temperature dependence of the yield strength of precipitate- comaining B2- ordered NiA1 was investigated by compression tests over the temperature range of 673-1273K. The fine precipitation of α-Fe was found to enhance greatly the low and intermediate temperature yield strength. When the deformation temperature is over 1073K, the strength of precipitate- containing NiA1 was comparable to ternary solid solution hardening NiA1-Fe. Dislocations bypass the particles during deformation and typical Orowan loops were observed surrounding the or-Fe particles after deformation.

关键词: nickel aluminide , null , null , null , null

PRECIPITATION AND MICROSTRUCTURE OF Cr MODIFIED Al3Ti

W.H. Tian

金属学报(英文版)

The microstructures of Cr modified Al3 Ti containing Al2 Ti and L10-AlTi precipitateshave been investigated in terms of transmission electron microscopy ( TEM). Fine pre-cipitation of Al2 Ti (Ga2Hf type structure) and L 1o-AlTi(Cr) occurs in L l2-Al3 Ti(Cr)by aging around 973K. The aging behavior was investigated by microhardness mea-surements. TEM observations revealed that plate-like Al2 Ti precipitates lie on { 100}planes of the L12-Al3 Ti(Cr) matrix with the c axis of the tetragonal phase perpendic-ular to the thin plate. As contrast with Al2 Ti precipitates, L1o-AlTi(Cr) precipitatesform thin plate and lie on {100} planes of L12-Al3Ti(Cr) matrix at the initial agingtime and for long time aging the habit plane of the thin plate deviated from {100}plane and finally formed a kinked plate. The coherency stresses across the precipi-tate/matrix interface are considered to be the main factor controlling the precipitatemorphology.``

关键词: titanium aluminide , null , null , null , null

PRECIPITATION BEHAVIOR OF Co PHASES IN B2-ORDERED(Ni,Co)Al COMPOUND

W.H. Tian , A.L. Fan

金属学报(英文版)

The precipitation behavior of Co phases in B2-ordered (Ni, Co)Al has been investigatedin terms of transmission electron microscopy. Fine precipitation off cc-Co occurs in(Ni, Co)Al by aging at temperature over 973K. The orientation relationship betweenthe fcc-Co precipitates and the B2-(Ni, Co)Al matrix follows the Kurdjumow-Sachs(K-S) orientation relation. But when the aging temperature is under 873K the Coprecipitates have a hcp crystal structure. The orientation relationship between thehcp-Co precipitates and the B2-(Ni, Co)Al matrix follows the Burgers orientation re-lation. (Ni, Co)Al is hardened appreciably by the fine precipitation of both the fcc-Coand hcp-Co phases. The temperature dependence of the yield strength of precipitate-containing B2-ordered (Ni, Co)Al was investigated by compression tests over the rangeof 298-1273K. The fine precipitation of Co phases enhances greatly the low and in-termediate temperature yield strength. When the deformation temperature was over873K, the strength of precipitate-containing (Ni, Co)Al is comparable to ternary dual-phase (Ni, Co)Al+Ni3Al alloy.

关键词: nickel aluminides , null , null , null

PRECIPITATION HARDENING IN B2-ORDERED NiAl BY Ni2AlTiCOMPOUND

W.H. Tian

金属学报(英文版)

Microstructural variations and correlated hardness changes in B2-ordered NiAl containing fine precipitation of Ni2AlTi have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that the L21-type Ni2AlTi precipitates keep a lattice coherency with the NiAl matrix at the beginning of aging. By longer periods of aging Ni2AlTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. The temperature dependence of the yield strength of precipitate-containing B2-ordered NiAl was investigated by compression tests over the temperature range of 873-1273K. The fine precipitation of Ni2AlTi was found to enhance greatly the yield strength and the high-temperature strength is comparison with that of superalloy Mar-M200.

关键词: NiAl intermetallics , null , null , null , null

C和W注入H13钢纳米结构和抗腐蚀特性

张通和 , 吴瑜光 , 易仲珍 , 张旭 , 梁宏 , 马芙蓉 , 王晓妍

材料热处理学报 doi:10.3969/j.issn.1009-6264.2001.03.015

用多次扫描电位法研究了C和W单独及双注入H13钢对抗腐蚀特性的影响、抗腐蚀相生成的条件及其对抗腐蚀特性的作用,对改性机理进行了讨论.实验结果表明,碳、钨单独和双注入H13钢钨和碳可在注入层超饱和分布,特征为类高斯分布.双注入可在注入层中形成弥散的碳化钨WC和W2C、中间相Fe2W、铁钨碳化物FeW3C、Fe6 W6C和铁的碳化物Fe5C3,Fe3C,Fe2C等.其形状为丝状纳米相,丝状相沿样品法线生长.这种结构使注入层强化,增强了表面抗腐蚀特性;钨和碳双注入同时具有钨和碳单注入的优势,能更有效地提高H13钢的抗腐蚀性,随着W和C注入剂量的增加,抗腐蚀特性逐步增强;样品W5C5的Jp经55个周期腐蚀后,约为H13钢Jp的1/30.

关键词: C和W注入 , , 抗腐蚀特性 , 电化学测量

LF炉冶炼过程钢中w(H)控制的实践

王瑾 , 廖明 , 李斌

钢铁研究

在2008年重钢的探伤钢CDQ207生产中,钢中氢成为影响钢板探伤合格率的主要因素之一.通过加强合金烘烤、控制精炼环节原辅料水分等技术管理措施,强化LF过程w(H)控制,充分发挥LF精炼功能,确保了大部分炉次钢中w(H)控制在合理范围内.2009年1-10月探伤钢探伤综量合格率为95.93%,较好地完成了项目指标.

关键词: 探伤 , 控氢 , LF , 合金烘烤

不同金属基体上W-C:H溅射薄膜的摩擦学性能

郑军 , 周晖 , 杨拉毛草 , 张延帅 , 翟广泉

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2015.01.015

采用非平衡磁控溅射技术在40Cr、9Cr18、GCr15、TC4及LY12等5种金属基体上沉积了钨掺杂含氢类金刚石(W-C:H)薄膜.采用Raman光谱仪、扫描电子显微镜、纳米硬度计及纳米划痕仪分别测试了薄膜的微结构、厚度、硬度及附着力,采用球-盘摩擦试验机及光学轮廓仪分别在干摩擦和PFPE脂润滑条件下评价了5种金属材料基体上薄膜的摩擦磨损性能.薄膜性能测试结果显示,该厚度为1μm的薄膜具有典型的类金刚石结构,硬度与弹性模量分别为11.56和128.34 GPa,附着力为645 mN;摩擦试验结果显示,在干摩擦条件下几种金属基体表面W-C:H薄膜的摩擦因数和磨损率差别比较显著,而在脂润滑条件下基体材料的影响较小;与干摩擦条件相比,脂润滑条件下薄膜的磨损可减少60% ~75%;在干摩擦与脂润滑条件下,9Cr18与40Cr基体上的W-C:H薄膜摩擦体系分别具有最小的磨损率1.71×10-7 mm3/(N·m)及4.55×10-8 mm3/(N·m).

关键词: W-C:H薄膜 , 摩擦学 , PEPE润滑脂 , 力学性能 , 非平衡磁控溅射

H13、3Cr2W8V和1.2367热疲劳性能的对比研究

陈英伟 , 吴晓春

钢铁研究学报

采用自约束热疲劳试验方法分别对H13、3Cr2W8V和1.2367钢进行热疲劳试验,对比分析表面裂纹形貌与截面裂纹深度,计算热疲劳损伤因子.利用Gleeble-3500对材料进行高温抗压实验,并对材料的组织进行SEM观察和EDS分析,研究热疲劳裂纹的萌生、扩展与材料强度和韧性的关系.研究表明:1.2367钢热疲劳后,表面裂纹十分均匀、细小,没有形成主裂纹,其热疲劳抗力高于H13钢和3Cr2W8V.1.2367较高的强度提高了材料热疲劳裂纹萌生的抗力,材料的热疲劳性能不仅取决于强度与硬度,也取决于良好的冲击韧性.

关键词: H13 , 3Cr2W8V , 1.2367 , 热疲劳性能 , 损伤因子

H13、3Cr2W8V和1.2367热疲劳性能的对比研究

陈英伟 吴晓春

钢铁研究学报

采用自约束热疲劳试验方法分别对H13、3Cr2W8V和1.2367钢进行热疲劳实验,对比分析表面裂纹形貌与截面裂纹深度,计算热疲劳损伤因子。利用Gleeble-3500对材料进行高温抗压实验,并对材料的组织进行SEM观察和EDS分析,研究热疲劳裂纹的萌生、扩展与材料强度和韧性的关系。研究表明:1.2367钢热疲劳后,表面裂纹十分均匀、细小,没有形成主裂纹,其热疲劳抗力高于H13钢和3Cr2W8V。1.2367较高的强度提高了材料热疲劳裂纹萌生的抗力,材料的热疲劳性能不仅取决于强度与硬度,也取决于良好的冲击韧性。

关键词: H13;3Cr2W8V;1.2367;热疲劳性能;损伤因子

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