材料期刊网

PREPARATION OF ULTRAFINE POWDER OF Fe AND ZrO_2 WITH METASTABLE PHASES BY HIGH POWER LASER BEAMS

XU Huibin TAN Shusong Technische Universitat Berlin , FRG XU Huibin Dipl.-Ing , FB9 , Physikalische Ingenieurwissenschaft , HF1 , TU Berlin , 1000 Berlin 12 , FRG

金属学报(英文版)

The radiation of material surface by high intensity laser beams is used to produce the uhrafine powder of pure Fe and ZrO_2.The morphology,size and phases of the powder were examined by X-ray diffraetometer,scanning electron microscopy as well as transmission electron microscopy.In pure Fe a considerable quantity of γ-phase was found in the powder.In ZrO_2 powder,instead of stable phase,two metastable phases appeared.

关键词: laser beam , null , null

EFFECT OF NANOCRYSTALLIZATION ON THE SCALING OF NiAl AT 1000℃ IN AIR

S.L.Yang , Fuhui Wang , S.L.Zhu

金属学报(英文版)

The oxidation behavior of a magnetron sputtered nanocrystalline NiAl coating wasinvestigated at 1000℃ in air. Comparing with cast NiAl and NiAl-0.1at.%Y alloysreveals influences of nanocrystallization as well as yttrium addition on the oxidationbehavior of NiAl. Results show that a phase transformation from metastable θ-Al2O3to stable α-Al2O3 occurred in scales, which was accelerated by the microcrystallizationand retarded by the addition of Y. The addition of Y as well as the nanocrystallizationreduced the void formation at the interface between the scale and the substrate.

关键词:

ISOTHERMAL SECTION AT 1000 AND 1100℃ OF Fe-Mn-Al PHASE DIAGRAM

LIU Xingjun HAO Shiming SUN Rongyao Northeast University of Technology , Shenyang , China Department of Materials Science and Engineering , Northeast University of Technology , Shenyang 110006 , China

金属学报(英文版)

Phase equilibria at Fe-Mn side of isothermal section at 1000 and 1100℃ in Fe-Mn- Al system have been determined using the diffusion couple technique and metallography. A three-phase,α+γ+β,region was found at 1000℃.The method of solid/gas diffusion couple used to determine equilibrium phase composition is believed to be feasible for the system containing volatile component.

关键词: Fe-Mn-Al system , null , null

新型镍基高温合金在950℃和1000℃的氧化行为

赵双群 , 董建新 , 张麦仓 , 谢锡善

稀有金属材料与工程

利用热重分析法、XRD和SEM(EDX)研究了1种新型镍基高温合金在950℃和1000℃的高温氧化行为.合金在950℃氧化时,氧化增重遵循抛物线规律,表面氧化膜无剥落,在1000℃氧化时表面氧化膜出现剥落,仍近似遵循抛物线规律.氧化膜由Cr2O3,Ni,Co)Cr2O4,TiO2,SiO2和A12O3组成,并有内氧化现象发生.合金在1000℃的氧化速度比在950℃时约高出1个数量级.根据氧化膜的组成进一步分析了合金的氧化机理.

关键词: 镍基高温合金 , 氧化动力学 , 氧化机理

Oxidation Behavior of Graded NiCrAlYRe Coatings at 900, 1000 and 1100 A degrees C

Oxidation of Metals

A graded NiCrAlYRe coating was prepared by combining arc ion plating (AIP) with chemical vapor deposition (CVD) aluminizing. Quasi-isothermal oxidation tests of the graded NiCrAlYRe coating and the conventional NiCrAlYRe coating were performed in air at 900, 1000 and 1100 A degrees C for up to 1000, 1000 and 200 h, respectively. The results showed that the graded NiCrAlYRe coating exhibited better long time oxidation resistance than the conventional NiCrAlRe coating. This favorable oxidation behavior was attributed to the rapid formation of a protective alpha-Al(2)O(3) scale and a sufficient Al reservoir. The structures and morphologies of oxide scales varied under different oxidation conditions. theta-Al(2)O(3) was observed on both coatings during oxidation at 900 A degrees C, however, the graded coating showed more favorable conditions for theta-Al(2)O(3) to grow than the conventional coating. For the graded coating, phase transformation from theta-Al(2)O(3) to alpha-Al(2)O(3) resulted in a sharp decrease in the parabolic rate constant k(p) between 900 and 1,000 A degrees C.

关键词: Rhenium;Oxidation;alpha-Al(2)O(3);theta-Al(2)O(3);Phase;transformation;cyclic-oxidation;alloys;rhenium;microstructure;implantation;improvement;resistance;additions;growth;scale

高铝1000 MPa级热镀锌双相钢的组织和性能

卢淋 , 唐荻 , 江海涛

材料热处理学报

实验室研发了一种高铝1000 MPa级的冷轧热镀锌双相钢,从化学成分、热镀锌退火工艺以及显微组织和性能等方面对其进行实验研究.实验结果表明:实验钢的Ac1、Ac3、Ms分别为757、950、410℃,经过热镀锌退火后,实验钢的室温组织为典型的马氏体+铁索体双相组织,马氏体精细结构为板条状,且随着退火温度的升高,马氏体含量增加,屈服强度和抗拉强度升高,伸长率保持在12％以上.

关键词: 高铝 , 热镀锌双相钢 , CCT曲线 , 组织性能

梯度NiCrAlY涂层的1000和1100 ℃氧化行为研究

于大千 , 卢旭阳 , 马军 , 姜肃猛 , 刘山川 , 宫骏 , 孙超

金属学报 doi:10.3724/SP.J.1037.2012.00024

采用电弧离子镀技术及后续热处理工艺在镍基高温合金上制备了均匀NiCrAlY涂层和梯度NiCrAlY涂层, 分析了2种涂层的组织结构, 对比研究了2种涂层静态空气下1000和1100 ℃恒温氧化行为以及1100 ℃的循环氧化行为. 结果表明: 均匀NiCrAlY涂层由γ'/γ相和少量β-NiAl相、α-Cr相组成, 成分分布均匀;梯度NiCrAlY涂层具有外层富Al和内层富Cr的结构, 其中外层由β-NiAl相和少量γ'/γ相、α-Cr相组成. 一方面, 梯度涂层的初始Al含量较高;另一方面, 氧化过程中其富Cr区两侧出现了对富Al区的Al向基体扩散起阻碍作用的Cr(W)析出带.这两方面使梯度涂层长时间维持更多的Al存储相, 提升了氧化膜的迅速生成及再生成能力,从而使涂层具有较好的抗氧化性能.

关键词: 电弧离子镀 , gradient coating , high temperature oxidation

含铝TRIP1000钢的断裂机制

周磊，黄澍，符仁钰，张梅，李麟

钢铁研究学报

通过在两相区温度和贝氏体区温度等温处理制备强度达1000MPa、伸长率为243%的含铝低硅TRIP钢，采用扫描电镜进行原位拉伸试验和能谱分析，研究其断裂机制。结果表明，在拉应力作用下，铁素体内部位错沿滑移带运动到晶粒边界引起位错塞积产生应力集中，同时铁素体与周围硬质相之间的结合力相对较弱，由于应力的作用而萌生微孔。微孔在应变应力作用下扩展，贯通，形成裂纹，穿过铁素体。裂纹在扩展过程中遇到硬质相贝氏体时沿其边缘行走。当遇到残余奥氏体时，裂纹前端的应力集中使得残余奥氏体转变为马氏体,产生相变诱发塑性，且因为裂纹前端的应力集中得以释放而钝化，随应力增加裂纹发生扭折，转向扩展，直至断裂。由断口韧窝形貌判断其断裂形式属于塑性断裂。

关键词: TRIP1000 , insitu tensile test , fracture mechanism

含铝TRIP1000钢的断裂机制

周磊 , 黄澍 , 符仁钰 , 张梅 , 李麟

钢铁研究学报

通过在两相区温度和贝氏体区温度等温处理制备强度达1000MPa、伸长率为24.3%的含铝低硅TRIP 钢,采用扫描电镜进行原位拉伸试验和能谱分析,研究其断裂机制.结果表明,在拉应力作用下,铁素体内部位错沿滑移带运动到晶粒边界引起位错塞积产生应力集中,同时铁素体与周围硬质相之间的结合力相对较弱,由于应力的作用而萌生微孔.微孔在应变应力作用下扩展,贯通,形成裂纹,穿过铁素体.裂纹在扩展过程中遇到硬质相贝氏体时沿其边缘行走.当遇到残余奥氏体时,裂纹前端的应力集中使得残余奥氏体转变为马氏体,产生相变诱发塑性,且因为裂纹前端的应力集中得以释放而钝化,随应力增加裂纹发生扭折,转向扩展,直至断裂.由断口韧窝形貌判断其断裂形式属于塑性断裂.

关键词: TRIP1000 , 原位拉伸 , 断裂机制

梯度NiCrAlY涂层的1000和1100℃氧化行为研究

于大千 , 卢旭阳 , 马军 , 姜肃猛 , 刘山川 , 宫骏 , 孙超

金属学报 doi:10.3724/SP.J.1037.2012.00024

采用电弧离子镀技术及后续热处理工艺在镍基高温合金上制备了均匀NiCrAlY涂层和梯度NiCrAlY涂层,分析了2种涂层的组织结构,对比研究了2种涂层静态空气下1000和1100℃恒温氧化行为以及1100℃的循环氧化行为.结果表明:均匀NiCrAlY涂层由γ'/γ相和少量β-NiAl相、α-Cr相组成,成分分布均匀；梯度NiCrAlY涂层具有外层富Al和内层富Cr的结构,其中外层由β-NiAl相和少量γ'/γ相、α-Cr相组成.一方面,梯度涂层的初始Al含量较高；另一方面,氧化过程中其富Cr区两侧出现了对富Al区的Al向基体扩散起阻碍作用的Cr(W)析出带.这两方面使梯度涂层长时间维持更多的Al存储相,提升了氧化膜的迅速生成及再生成能力,从而使涂层具有较好的抗氧化性能.

关键词: 电弧离子镀 , 梯度涂层 , 高温氧化