L.Li 1)
,
Z. P.Wang. 2)
,
Z.K.Qu 1)
,
D.M.Jia 3) and Z.Jiang 4) 1) Mechanical Engineering College
,
Shenyang University
,
Shengyang 110044
,
China 2) Harbin Research Institute of Welding
,
Harbin 150080
,
China 3) Information Engineering Collage
,
Shenyang University
,
Shengyang 110044
,
China 4) Materials Engineering College
,
University of Science and Technology Beijing
,
Beijing 100083
,
China
金属学报(英文版)
A novel test method of measuring the interface bond strength between a thermal sprayed coating and substrate is put forward first in this paper. The test method is simple and reliable, and exists no any inherent shortcoming and controversy. The interface bond strength obtained by the test method is completely the inherent property of the interface and depends only on coating material properties, spray conditions, and technique of depositing the coating. By extensive tests, it is shown that the test tesults are very tepeatable and reliable. Furthermore, from this test, the critical coating thickness under which the coating spall can not emerge is also obtained.
关键词:
coating
,
null
,
null
,
null
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
Hot compression tests of a P/M Ti-47Al-2Cr-2Nb-0.2W-0.15B (at. pct) alloy were carried out on a Gleeble-3800 simulator at the temperatures ranging from 950 degrees C to 1250 degrees C with the strain rates ranging from 10 s(-1) to 10(-3) s(-1). Optical microscope, electron backscatter diffraction technique, and transmission electron microscope were employed to investigate the microstructure evolution and nucleation mechanisms of dynamic recrystallization. It was found that the flow behavior is a function of the deformation temperature and strain rate. The dependence of the peak stress on the deformation temperature and strain rate can be expressed by a hyperbolic-sine type equation. The activation energy for the alloy is calculated to be 315 kJ/mol. The size of the dynamically recrystallized grains decreased with increasing the value of parameter Z. However, the size of dynamically recrystallized grains almost remains constant with increasing deformation strain. At the early stage the dominant nucleation mechanism of dynamic recrystallization in the alloy is the discontinuous dynamic recrystallization, which is characterized by the bulging of the original grain boundaries and the deformation twinning. As the deformation strain increased, the continuous dynamic recrystallization characterized by progressive subgrain rotation occurred. Twinning was observed under all deformation conditions. The spheroidization of the alpha(2) took place at the compression temperature 950 degrees C and the strain rate 10(-3) s(-1). (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Titanium aluminide;Powder metallurgy;Hot deformation behavior;Dynamic;recrystallization;dynamic recrystallization;hot deformation;submicrocrystalline;structure;aluminide alloys;intermetallics;prediction;working;creep;steel;twin
郭世海
,
冯则坤
,
王新林
,
何华辉
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2010.02.002
采用普通陶瓷工艺制备了Gd掺杂的Co2Z型平面六角铁氧体3(Ba0.5Sr0.5)·2Co0·0.05Gd2O3·10.8Fe203,对其微结构和高频性能进行了研究.结果表明,少量掺杂Gd的Co2z型铁氧体仍具有单相的Z型平面六角结构,其磁导率实部μ'明显提高,可达到13,而截止频率仍大于1GHz,具有较好的高频性能.随着烧结温度的提高,材料的磁导率实部μ'增大,但截止频率下降.少量Gd的掺杂对Co2Z型铁氧体的复介电常数值没有明显影响,但材料的铁电共振峰向高频区移动.
关键词:
六角晶系铁氧体
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Co2Z型铁氧体
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磁性能
,
稀土
王其坤
,
胡海峰
,
陈朝辉
,
张玉娣
,
罗征
稀有金属材料与工程
针对2D C/SiC复合材料存在碳布层间缺乏纤维增强,层间结合较差的问题,提出通过Z-向穿刺工艺提高碳布层间结合,克服材料使用时可靠性不高的问题,并比较了穿刺工艺对复合材料微观结构和力学性能的影响.结果表明,通过Z-向穿刺工艺制得试样2D C/SiC-Z_(pin)的弯曲强度、弯曲模量和剪切强度分别为247.8 MPa、37.8 GPa和32.1 MPa,而未穿刺试样2D C/SiC的弯曲强度、弯曲模量和剪切强度分别只有219.3 MPa、34.4 GPa和23.3 MPa,由此可见,采用Z-向穿刺工艺能明显提高复合材料的力学性能.微观结构分析认为,试样力学性能提高的根本原因在于采用Z-向穿刺纤维加强了碳布层间结合,使材料具有较好的整体性,克服了复合材料层间结合较弱对力学性能带来的不利影响.
关键词:
2D
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C/SiC
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Z-向穿刺
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微观结构
,
力学性能
王军朋
,
李凤
,
敖靖
,
焦丽娜
,
李春梅
,
陈志谦
无机材料学报
doi:10.15541/jim20140463
采用第一性原理计算研究了超硬材料z-BC2N的弹性各向异性性质、应力-应变关系、硬度及最小热导率性质.计算得到的晶体力学行为判据 B/G 为 0.87, 泊松比为 0.084, 普适弹性各向异性指数为 0.09992.[100]晶向上最大拉伸强度达到180 GPa,(100)[010]应变方向上最大剪切强度达到160 GPa,维氏硬度值为77.07 GPa.基于Cahill模型得到的最小热导率为6.811 W/(m·K).结果表明: z-BC2N是脆性材料且力学稳定性良好,有非常高的拉伸强度、剪切强度, 体弹模量为各向同性, 杨氏模量各向异性程度不大.z-BC2N 的最小热导率低于金刚石的最小热导率.
关键词:
超硬材料
,
弹性性质
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各向异性
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热导率
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
Liubing WANG
金属学报(英文版)
Tests under mechanical strain control were performed to investigate the TMF behavior of Z2CND18.12N within the temperature range between 150-550℃. Different strain amplitudes and phase-angles were applied. Total strain controlled low cycle fatigue test was also performed at the peak temperature of TMF cycling. The results show that the cyclic stress response of the material displayed an initial hardening regime followed by a saturation period and then cyclic softening till failure. The TMF cycling leads to the development of significant amounts of mean stress. Some life prediction models were employed to predict the TMF life of Z2CND18.12N, and the results indicate that the energy-based models provide good prediction on the thermal-mechanical fatigue behaviors of this material. An optical microscopic observation shows that the surface crack initiations and crack propagations are typically transgranular mode.
关键词:
Thermomechanical fatigue
