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Density of Ni-Cr Alloy in the Mushy State

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Journal of Materials Science & Technology 2003年第2期19卷 107-110页

作者： feng XIAO1) Joining and welding research institute, osaka university, osaka 567-0047, japan2) School of Materials Science and Engineering Tianjin university, Tianjin 300072, China Joining and welding Res. Inst. Osaka Univ. Osaka 567-0047 Japan Sch. of Mat. Sci. and Eng. Tianjin Univ. Tianjin 300072 China

The density of Ni-Cr alloy in the mushy state has been measured using the modified sessile drop method. The density of Ni-Cr alloy in the mushy state was found to decrease with increasing temperature and Cr concentration in alloy. The molar volume of Ni-Cr alloy in the mushy state therefore increases with increasing the Cr concentration in alloy. The ratio of the difference of density divided by the temperature difference between liquidus and solidus temperatures decreases with increasing Cr concentration. The density of the alloy increased with the precipitation of a solid phase in alloy during the solidification process. The temperature dependence of the density of alloy in the mushy state was not linear but biquadratic.

关键词： Ni-Cr alloy Density Molar volume Mushy state Modified sessile drop method

INTERfACIAL STRUCTURE AND PHASE REACTION IN SiC/NiCr ALLOY JOINT

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Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 28-32页

作者： J. C. feng M. Naka J. C. Schuster(School of Materials Science and Engineering, Harbin institute of Technology, Harbin, 150001, China Joining and welding research institute, osaka university, Mihogaoka 11 - 1, Ibaraki, osaka 567, japan institute of P

Bonding of SiC to SiC using Ni and Ni - 25at%Cr foils was performed at high *** structures and reaction phases were investigated by EPMA analyses and XRD diffraction method, re- spectively. At a bonding temperature of 1273K Ni reacts with SiC and forms various Ni silicides con- taining graphite baside SiC. Ni3Si without graphite was formed at Ni *** interface structure of SiC/Ni joint was SiC/Ni2Si + C/Ni31 Si12 + G/Ni3 Si/Ni. At the interface between SiC and Ni- 25at%Cr alloy the Ni silicide was only Ni2Si at the same bonding temperature,and further(Cr, Ni)7 (Si, C)3 carbide was formed between Ni silicide + graphite zone and Ni - 25at%Cr *** interface structure of SiC/Ni - 25at%Cr alloy was SiC/Ni2Si + C/(Cr, Ni)7 (Si, C)3+Ni(ss. Cr, Si)/Ni - 25at%Cr.

关键词： interfacial structure phase reaction SiC Ni - Cr

EffECT Of Ti CONTENT ON THE MICROSTRUCTURE AND PROPERTIES Of Si_3n_4/Si_3N_4 JOINT BRAZED USING Cu-Zn-Ti ALLOY

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Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 23-27页

作者： M. Naka J. Zhang H. Y. fang (1.Joining and welding research institute, osaka university, japan 2)School of Materials Science and Engingeering, Harbin institute of Technology, Harbin 150001, China)

St3N4 ceramic was brazed using a filler of Cu - Zn - Ti alloy under the brazing condition of 1223K and 1.8ks. When the Ti content in the alloy is 20% at., the average shear strength of the joint is 265MPa. By using EPMA and XRD analysis, the metallurgical behavior of the interface between the filler alloy and Si3N4 matrix was studied,which affected the joint *** was found that with in- creasing Ti content from 5% to 20%at., the thickness of the brazing seam decreases and the amount of the reactant(Ti5Si3, TiN and Ti2N etc. ) increases,resulting in an obvious increase of the shear strength of the joint.

关键词： Si_3N_4 ceramic Ti brazing microstructure mechanical property

Hardness Measurement of (TiB_2-TiAl)/TiAl Symmetrically function Gradient Materials

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Journal of Wuhan university of Technology(Materials Science) 2002年第1期17卷 1-3页

作者：梅炳初 WuhanuniversityofTechnology

( TiB2-TiAl)/TiAl symmetrically function gradient materials ( fGM) were prepared by spark plasma sintering ( SPS). Owing to the difference, of the thermal expansion coefficients between TiB2 and TiAl, a compressive surface stress was introduced to the fGM fry the thermal expansion mismatch. The hardness values of the uniform materials and the fGM were tested, respectively. for the fGM with a compressive surface stress, hardness is obviously superior to that of the uniform material. When the fGM was subjected to heat treatment, the hardness decreased due to a partial relaxation of the compressive surface stress.

关键词： hardness measurement function gradient materials composite

Mathematical Modeling of Metal Active Gas (MAG) Arc welding

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Journal of Materials Science & Technology 2001年第1期17卷 167-168页

作者： Takayoshi Ohji Yoko Tsuji fumikazu Miyasakn and Takeshi Yamamoto Department of Adaptive Machine Systems, osaka university 2-l, Yamada-oka, Suita, osaka, 565-0871, japan Dep. of Adaptive Machine Syst. Osaka Univ. Osaka 565-0871 Japan

In the present paper. a numerical model for MAG (metal active gas) arc welding of thin plate has been developed. In MAG arc welding, the electrode wire is melted and supplied into the molten pool intermittently. Accordingly, it is assumed on the modeling that the thermal energy enters the base-plates through two following mechanisms, i.e., direct heating from arc plasma and 'indirect' heating from the deposited metal. In the second part of the paper, MAG arc welding process is numerically-analyzed by using the model. and the calculated weld bead dimension and surface profile have been compared with the experimental MAG welds on steel plate. As the result. it is made clear that the model is capable of predicting the bead profile of thin-plate MAG arc welding, including weld bead with undercutting.

关键词： arc welding welding process surface profile numerical model molten pool thin plate arc plasma

多层焊焊接应力分布对管子局部热处理应力释放准则的影响

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上海交通大学学报 2000年第12期34卷 1618-1621页

作者：陆皓汪建华村川英一上海交通大学材料科学与工程学院上海200030 大阪大学接合科学研究所

采用有限元方法构造了轴对称模型下多层焊应力分布 ,用粘弹塑性有限元方法对管子多层焊后不同局部热外理条件下应力分量的分布情况进行了研究 .结果表明 ,管子内、外侧残余应力和加热宽度表现出不同的规律 :管子外侧的残余应力随加热宽... 详细信息

采用有限元方法构造了轴对称模型下多层焊应力分布 ,用粘弹塑性有限元方法对管子多层焊后不同局部热外理条件下应力分量的分布情况进行了研究 .结果表明 ,管子内、外侧残余应力和加热宽度表现出不同的规律 :管子外侧的残余应力随加热宽度的增加缓慢下降 ;管子内侧的残余应力在较小的加热宽度下可以得到有效消除 .残余应力与加热宽度关系表现为两种类型 :一种是理想衰减型 ;另一种为局部最小型 .多层焊形式下的残余应力与加热宽度的关系表现为后一种型式 .加热宽度 2 B=5 Rt较为合理 .过大的加热宽度对局部热处理应力释放的作用不大 .最后 ,进行了管子的多层焊和局部热处理试验 ,并采用 X-射线法对局部热处理后的应力进行了测量 .

关键词：局部热处理多层焊焊接应力分布加热宽度

Relative Damage Stress: Dominant Mechanical factor for the failure of Soldered Joints under Temperature Cycling

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Journal of Materials Science & Technology 2001年第1期17卷 193-194页

作者： Xin MA Yiyu QIAN and Hongyuan fANG National Key Laboratory of welding, Harbin institute of TechnologY, Harbin 150001, China f. Yoshida Department of Mechanical Engineering, Hiroshima university, Higashi-Hiroshima 739, japan Natl. Key Lab. of welding Harbin Inst. of Technol. Harbin 150001 China

By temperature normalization of the concept of equivalent damage stress proposed by Lemaitre, a new concept of relative damage stress has been put forward as the dominant mechanical factor for the failure of soldered joints under temperature cycling. finite element numerical simulation results showed that the highest value of relative damage stress occurred at the high temperature hold time during temperature cycling history.

关键词： Damage Stress damage stress simulation results soldered joints

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大功率光纤激光焊焊缝跟踪偏差红外检测方法

物理学报 2011年第8期60卷 737-744页

作者：高向东莫玲仲训杲游德勇 Katayama Seiji 广东工业大学机电工程学院广州510006 大阪大学接合科学研究所

精确控制激光束使其始终对准并跟踪焊缝是保证激光焊接质量的前提.针对大功率(激光功率10kW)光纤激光焊接304型不锈钢紧密对接焊缝(间隙为0—0.1mm),研究一种基于红外热像的焊缝跟踪偏差检测新方法.采用红外传感高速摄像机摄取焊接区域... 详细信息

精确控制激光束使其始终对准并跟踪焊缝是保证激光焊接质量的前提.针对大功率(激光功率10kW)光纤激光焊接304型不锈钢紧密对接焊缝(间隙为0—0.1mm),研究一种基于红外热像的焊缝跟踪偏差检测新方法.采用红外传感高速摄像机摄取焊接区域熔池红外动态热像,分析激光束对准和偏离焊缝中心时的熔池温度分布和红外辐射特性,以熔池匙孔形变参数和热堆积效应参数作为激光束与焊缝中心偏差检测特征值,通过图像识别技术研究和分析特征值与焊缝偏差之间的关系.激光焊接试验结果表明,熔池匙孔形变参数和热堆积效应参数与焊缝偏差之间存在密切的数学关联,能有效判断和检测激光束与焊缝之间的偏差.

关键词：大功率光纤激光焊焊缝跟踪偏差红外热像检测

EVALUATION Of EMBRITTLEMENT BEHAVIOR DUETO SENSITIZATION IN A CRYOGENIC AUSTENITICSTAINLESS STEEL BY MEANS Of SMALL PUNCHAND fRACTURE TOUGHNESS TESTS

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Acta Metallurgica Sinica(English Letters) 1997年第3期10卷 239-248页

作者： S.C Liu(research institute for fracture Technology faculty of Engineering, Tohoku university, Sendai, japan on leave from Dalian Railway institute, Dalian 116028, China)II-Hyun Kown T Hashida and H Takahashi(research institute for nacture Technology, fa

In order to evaluate the tendency of mechanical properties degrudation due to weld-ing and other processing in materials used for supporting coils in super conducting rnaguets utilized in thermonuclear jusion reactore, a small punch (SP) test was *** test, which was originally developed to study irradiation damage using miniatursized specimens was performed at 77 and 4 K for solution treated and sensitized JN1 austenitic stainless steel, a candidate cryogenic structural material. The area under the load-deflection curve up to the maximum applied load in SP test was defined as the SP enerpy, to characterize the resistance to fracture. Although solution treated material exhibited ductile fracture mode with high SP enerpy, embrittlement behavior due to sensitization at 650-800°for 1-5 h was shown clearlg by SP test with brittle intergranular fracture and decreased SP enerpy. Comparison of the results obtained by SP test with those by fracture toughness test showed the usefulness of SP test for evaluation of sensitization induced embrittlement at cryogenic temperature. The re-sults obtained in this study can be very usefol in predicting the degradation due to welding and other processing in cryogenic materials.

关键词： small punch test fracture toughness test cryogenic fracture behavior JN1 austenitic stainless steel embrittlement due to sensitization