检索结果-南通市图书馆

Effect of Thermal Cycling under Load on Martensite Transformat.on and Two-way Shape Memory Effect in a TiNi Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2001年第2期17卷 263-266页

作者： Liming WANG, Yufeng ZHENG, Wei CAI, Xianglong MENG and Liancheng ZHAO School of mat.rials sci.nce and Engineering, Harbin inst.tute of technol.gy, Harbin 150001, China Sch. of mat. sci. Harbin Inst. of Technol. Harbin 150001 China

The effect of thermal cycling under loading on martensitic transformat.on and two-way shape memory effect was investigated for Ti-49.8 at, pet Ni alloy. It is shown that M(s), and M(f) temperature increase with increasing the number of cycles, while A(s) and A(f) temperature decrease during thermal cycling. The total strain at and permanent strain epsilon (p) increase with increasing applied stress and number of cycles. The two-way shape memory effect can be improved by proper thermal cycling training under loading, while excessively high applied stress results in the deterioration of TWSME. The reason for the changes in martensitic transformat.on characteristics and two-way shape memory effect during thermal cycling under loading is discussed based on the analysis of microstructure by TEM observations.

关键词： TiNi Effect of Thermal Cycling under Load on Martensite Transformat.on and Two-way Shape Memory Effect in a TiNi Alloy

Development of mat.emat.cal Model on Preparation of Functionally Graded mat.rial by Co-sedimentation

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2001年第2期17卷 275-277页

作者： Zhongmin YANG, Lianmeng ZHANG and Qiang SHEN inst.tute of mat.rials sci.nce and Engineering, Wuhan University of technol.gy, Wuhan 430070, China inst. of mat. sci. Wuhan Univ. of Technol. Wuhan 430070 China

From the process of sedimentation the mat.emat.cal relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mat.emat.cal model was set up and simulated through the computer. At last the validity of mat.emat.cal model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.

关键词： Co Mo Development of mat.emat.cal Model on Preparation of Functionally Graded mat.rial by Co-sedimentation

Critical and Impeding Pressures of Al Evaporation during ISM Processing of NiAl

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2003年第6期19卷 571-575页

作者： Guizhong LIU, Jingjie GUO, Yanqing SU, Jingzhe GUO, Jun JIA and Hengzhi FUSchool of mat.rials sci.nce and Engineering, Harbin inst.tute of technol.gy, Harbin 150001, China Sch. of mat. sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

In this paper, the critical pressure pcrit and impeding pressure pimpe of the elemental evaporation were defined and studied based on the calculation of the relationship between the evaporation loss rate Nm and the chamber pressure p during melting of NiAl alloys. When the chamber pressure is lower than pcrit or higher than Pimpe Nm tends to be the maximum or minimum value and remains almost unchanged. However, declines sharply with the increase of the chamber pressure when pcrit

关键词： ISM process Al evaporation Critical pressure Impeding pressure

Raman Scattering and t-Phase Lattice Vibration of 3% (mole fraction) Y_2O_3-ZrO_2

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2004年第5期20卷 485-489页

作者： Xinglun TANG and Xinhua ZHENGSchool of mat.rials sci.nce and Engineering, Beijing inst.tute of technol.gy, Beijing 100081, China Sch. of mat. sci. and Eng. Beijing Inst. of Technol. Beijing 100081 China

The Raman spectra of 3% (mole fraction) Y2O3-ZrO2 (3Y) are obtained at different temperature from 77 K to 853 K. The results show that 260 cm-1 Eg and 460 cm-1 Eg modes on the spectra shift toward lower wave number with the increase of temperature; meanwhile, the continuity of the Half Width at Half Maximum (HWHM) and wave number (frequency) of Raman bands are broken and t-phase only partially transforms to m-phase at 523 K. Based on the experimental results, this paper discusses the t-phase lattice vibration of 3Y and presents the images of vibration displacement of six Raman-active modes for t-phase of ZrO2. The analysis indicates that there are diversities existing in the displacement of the atomic vibration of Raman-active modes because of their different symmetries at various temperature, which leads to the different change tendencies of Raman bands. Furthermore, the abrupt changes of some Raman-active modes indicating the atomic displacement are assumed to be the condensations of phonon modes in t

关键词： Raman scattering Zirconia Phase transition Condensation of phonon

Measurement and Analyses of Molten Ni-CO-Al Alloy Density

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2003年第5期19卷 388-390页

作者： Feng XIAO and Liang FANGDepartment of mat.rials sci.nce and Engineering, Chongqing inst.tute of technol.gy, Chongqing 400050, China Dept. of mat. sci. and Eng. Chongqing Inst. of Technol. Chongqing 400050 China

The density of molten Ni-Co-AI alloy was measured using a modified pycnometric method. It has been found that the density of the molten Ni-Co-AI alloy decreases with increasing temperature, Co concentration and the ratio of Co concentration to Ni concentration in the alloy. The coefficient of volume expansion of the molten Ni-Co-AI alloy decreases with increasing Co concentration and the ratio of Co concentration to Ni concentration. The temperature coefficient of density increases with increasing the Co concentration or the ratio of Co concentration to Ni concentration in the alloy. The density of the molten Ni-Co-AI alloy as functions of both temperature and Co concentration was expressed.

关键词： Density Modified pycnometric method Ni-Co-Al alloy

Kinetic Characteristic of Hydrogenation Zr-Ti-Cu-Ni-Be Bulk Amorphous Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2004年第2期20卷 157-159页

作者： Delin PENG, Jun SHEN, Jianfei SUN and Yuyong CHENSchool of mat.rials sci.nce and Engineering, Harbin inst.tute of technol.gy, Harbin 150001, China Sch. of mat. sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

The relationship between the hydrogen content and the microhardness and the charging period, the effect of hydrogen on the activation energy, the kinetics of glass transition and crystallization of Zr-Ti-Cu-Ni-Be bulk amorphous alloy were studied by differential scanning calorimetry (DSC) and the Kissinger equation. It shows that both of the hydrogen content and the microhardness are related to the charging period, and that the glass transition and crystallization behavior are associated with the heating rate, and possess the kinetic effect. Hydrogen increases the glass transition temperature and the crystallization temperature, decreasing the enthalpies in the different stages of crystallization. Hydrogen increases the activation energies of the glass transition and the crystallization and changes the kinetic effect. The dependent extent between the glass transition, the crystallization and heating rate decreases after hydrogen charging.

关键词： Bulk amorphous Hydrogenation Glass transition Crystallization Kinetic

Synthesis and Enhanced Superplasticity of the Zirconia-dispersed Alumina Nanocomposite

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2005年第1期21卷 79-82页

作者： Guoqing CHEN, Kaifeng ZHANG, Wenbo HAN and Junting LUOSchool of mat.rials sci.nce and Engineering, Harbin inst.tute of technol.gy, Harbin 150001, ChinaProf., Ph.D., Sch. of mat. sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

A series of alumina-zirconia composites with various grain sizes were prepared from the nano-sized powders with different agglomerations. Microstructural analysis of the sintered compacts indicates that the as-sintered mat.rial is a typical intra/inter granular nanocomposite with uniform distribution of the zirconia grains in the alumina mat.ix. Superplastic deep drawing test under different conditions demonstrates that dense Al2O3/ZrO2 samples with average grain size of 230 nm can be elongated to a dome height of at least 12 mm at the punch rate of 0.6 mm·min-1 at 1400℃. Further drawing tests show that for the composites with larger grain size, such elongation cannot be achieved at such a strain rate.

关键词： Nanocomposite Synthesis Microstructure Superplasticity

Study on the Thermal Expansion and Thermal Cycling of AlNp/Al Composites

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2002年第1期18卷 62-65页

作者： Qiang ZHANG, Gaohui WU, Dongli SUN and Bofeng LUANSchool of mat.rials sci.nce and Engineering, Harbin inst.tute of technol.gy, Harbin 150001, China [ Manuscript received January 8, 2001, in revised form April 13, 2001] Sch. of mat. sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

The AIN particle reinforced aluminum mat.ix composites with 50% volume fraction were fabricated by squeeze-casting technol.gy. The thermal expansion behavior and its response to thermal cycling were studied between 20℃ and 400℃. Compared with four theoretical models, the measured CTEs of the composite lie within the elastic bounds derived by Schapery’s analysis. Schapery’s model and Kerner’s model agree well with the CTEs of the composites at lower temperature and elevated temperature, respectively. Strain hysteresis was observed between heating and cooling curves during cycling. This was attributed primarily to the anelastic behavior of the mat.ix induced by mat.ix residual stresses.

关键词： AIN Aluminum mat.ix composite Thermal expansion Thermal cycling

Influence of Bias on the Properties of Carbon Nitride Films Prepared by Vacuum Cathodic Arc Method

在线全文

学校读者我要写书评

暂无评论

Journal of mat.rials sci.nce & technol.gy 2004年第6期20卷 735-738页

作者： Zhimin ZHOU, Lifang XIA and Mingren SUNSchool of mat.rials sci.nce and Engineering, Harbin inst.tute of technol.gy, Harbin 150001, China Sch. of mat. sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

Carbon nitride films have been synthesized in a wide range of biases from 0 to -900 V by vacuum cathodic arc method. The N content was about 12.0-22.0 at. pct. Upon increasing the biases from 0 to -100 V, the N content increased from 15.0 to 22.0 at. pct which could be attributed to the knot-on effect. While the further increasing biases led to the gradual falling of the N content to 12.0 at. pct at -900 V due to the enhancement of the sputtering effect. Below -200 V, with the increasing biases the sp2C fraction in the films decreased, as a result of vvhich the I(D)/I(G) fell in the Raman spectra and the sp peaks also showed the decreasing tendency relative to the s peaks in the VBXPS (valence band X-ray photoelectron spectroscopy). While above -200 V, the sp2C fraction increased and the films became graphitinized gradually, accompanying which the I(D)/I(G) rose from -200 V to -300 V and the Raman spectra even shovved the graphite characteristic above -300 V and the sp peaks rose again relative to the s peak. The carbon nitride films mainly consist of three types of bonding: CC, sp2CN and sp3CN bonds. In the first stage the sp3CN relative ratio rises and falls in the second stage, which corresponded well with the variation of the sp2C in the films. The subpiantation mechanism resulting from the effect of ion energy played an important role in deciding'the variation of the microstructure of the carbon nitride films.

关键词： Carbon nitride Vacuum cathodic arc Raman spectroscopy X-ray photoelectron spectroscopy