航空材料学报

MICRO5TRUCTURE AND MECHANICAL PROPERTIESOF Ni₃Al AND Ni₃Al COMPOSTIES BY SPRAY-DEPOSITION

Mi Guofa, Zeng Songyan, Li Qingchun, Tian Shifan, Zhao Xianguo, Ren Liping, Li Zhou, Liang Zhikai, Luo Zhiping

1995, 15(2): 1-7.

[Abstract](1459) [PDF 2353KB](161)

Abstract:
Ni3Al based Ni-Al-Mo superalloy and Ni3Al composites are successfully prepared by spray-deposition technique. Their microstructure and mechanical properties have been studied. At last,the paper brings forward a new forming mechanism about ceramic particulates reinforced composites.

EFFECT OF ADDITION OF ULTRAFINE POWDER(AlN+Al)ON SINTERING AND THERMAL CONDUCTIVITY OF FINE AlN POWDER

Li Xingguo, Zhang Tongjun, Zhao Xingzhong, Jiang Huien

1995, 15(2): 8-13.

[Abstract](1431) [PDF 386KB](197)

Abstract:
Mixed ultrafine powder of AlN+Al was produced by arc plasma method. This ultrafine powder wasmixed wlth fine AlN powder,obtained by carbonthermal reduction method and then sintered at 1973,2023 2073 and 2123K respectively.The experiment results,such as X ray diffrection,electron microscopy,thermal conductivity analysis and so on,show that the density and themal conductivity of the sintered samples increase with the addition of the ultrafine powder when sintering temperature is under 2123K,and decrease inversely when the temperature comes up to 2123K. In this paper,the condition andmechanism of the effects of addition of the ultrafine powder on the sintering and thermal conduction of thefine AlN powder are discussed.

STUDY ON TENSILE DEFORMATION MECHANISM OF A Ti₃Al ALLOY AT ROOM TEMPERATURE

Sun Fusheng, Gao Wen, Cao Chunxiao

1995, 15(2): 14-20.

[Abstract](1484) [PDF 451KB](216)

Abstract:
The dislocations(such as type) and slip systems of α2 phase(DO19 in structure)in a Ti-25Al-10Nb-3V-1Mo alloy after room-temperature tensile deformation were investigated in accordance withg invisibility criterion in a transmission electron microscope equipped with a side entry gonimeter stagecapable of a±45° tilt on the X or Y axis. Experiment results indicated that slip in α2 phase of Ti-25Al-10Nb-3V-1Mo alloy occurs predominantly on〈1120〉{1100},〈1120〉{0001} slip systems with occasionally〈1126〉{2021}present. The dislocations on pyramidal planes are dislocation pairs with corrugated appearance.

ON MICROSTRUCTURE OF Fe-10Ni-14Co STEEL WITH STANDARD HEAT TREATMENT

Ling Bin, Zhong Ping, Zhong Binwen, Gu Baozhu, Zhao Zhengye, Zhang Shaoqing, Pu Ruhou

1995, 15(2): 21-26,7.

[Abstract](1445) [PDF 405KB](157)

Abstract:
The microstructures of the Fe-10Ni-14Co steel tempered at 510℃ with different time were studied bytransmission electron microscopy(TEM).It has been found that the microstructure changed obviously from peak-aging to over-aging with the different tempered time at 510℃.

THE RETAINED AUSTENITE IN ISOTHERMALLY TRANSFORMED 40CrNi2Si2MoVA STEEL

Zhang Wei, Zhao Zhenye, Feng Yushu, Ling Bin

1995, 15(2): 27-33.

[Abstract](1428) [PDF 448KB](164)

Abstract:
Variations in morphology,amount,thermal and mechanical stabilities in tensile state of retained austenite in an ultrahigh strength low alloy steel 40CrNi2Si2MoVA,subjected to 270℃ isothermal transformation,were investigated in this paper.The results were compared with those obtained by conventional quenching and tempering heat treatment. Isothermal transformation of 40CrNi2Si2MoVA steel at 270℃ produced more retained austenite. its amount, morphology, distribution and stability varied with temper temperature. The optitnum combination of strength and toughness could be obtained by tempering at300℃ when the stability of retained austenite was highest. The results showed that the strain inducedtrans formation product of interlath retained austenite with lower mechanical stability was untempered lathmartensite, and of intralath retained austenite was twinned martensite. The stability of retained austenitein isothermally transformed 40CrNi2Si2MoVA steel was also discussed in terms of experimental results.

ON“WHITE SPOT”IN SECONDARY HARDENING STEEL 16Co14Ni10Cr2Mo

Jin Jianjun, Gu Baozhu, Wang Hongtao, Zhong Ping

1995, 15(2): 34-39.

[Abstract](1526) [PDF 364KB](157)

Abstract:
The macroscopical defect white spot in secondary hardening steel 16Co14Ni10Cr2Mo was investigatedusing microscope,microhardness,scanning electron microscop(SEM) and electron probe. The results showed that the white spot is a sort of segregation defect.Ni positive segregation results in the formationof white spots. The effects of white spot segregation on processing properties and mechanical propertis were discussed in this paper.

MICROWAVE SINTERING OF OXIDE CERAMICS

Wu Su, Lu Anli

1995, 15(2): 40-44.

[Abstract](1523) [PDF 303KB](232)

Abstract:
Microwave heating is becoming more and more attractive in the high temperature processing of ceramic materials due to its volumic heating, selective heating and rapidity.Variable kinds of oxide ceramics, including Y-TZP,zirconia toughened alumina(ZTA) and Al2O3,were microwave sintered in a home-designed microwave applicator.The processing procedures and sintering results were investigated and then compared to that of conventional sintering.

INFLUENCE OF RESIN STORAGE AT ROOM TEMPERATURE ON THE VISCOSITY AND THE TIME TO APPLY PRESSURE

Li Bing, Hong Xuhui, Wang Xiaowei

1995, 15(2): 45-48.

[Abstract](1501) [PDF 220KB](220)

Abstract:
5405 is modified BMI resin which is newly developed and used as matrix resin for high performence compesites.This paper discusses influence of 5405 resin storage at room temperature on the viscosity andthe time to apply pressure during the curing. The model and the calculation result has been given. It maybe valuable to the curing processing of 5405/fiber composites.

ESTIMATING THE MECHANICS PARAMETER OF COMPOSITE MATERIALS WITH PERFECT SPHERICAL RIGID INCLUSIONS

Lin Zheng, Yukio Hirose, Shouichi Ejiri

1995, 15(2): 49-56.

[Abstract](1473) [PDF 422KB](168)

Abstract:
Abstract The results of Y. Hirose and Z. Lin et.al.(1994) can be applied to discuss the average elastic-plasticbehavior of the composite material in both cases where either the composite material is subjected to pureshearing or is subjected only to axial stress.This composite material is composed of matrix of isotropicideal elastic plastic materials and perfect spherical rigid inclusions. The volume of any inclusion is smallerthan the volume of matrix, and the inclusions fit tightly against the matrix. Furthermore,the overall average elastic modul of the composite material is obtained and the way how to increase the average elasticmodul of the composite material is given. The research result shows the relationship between the yieldstress of composite material and the yield stress of matrix material. It gives a quantitative evaluation of theaverage overall hardening rate after the matrix initial yielding and the overall stress at the first yielding.

HYDRO6EN AND HYDROGEN EMBRITTLEMENT IN ALUMINUM LITHIUM ALLOYS

Jiao Chengge, Yu Guifu, Liu Bocao, Yan Minggao

1995, 15(2): 57-62.

[Abstract](1568) [PDF 386KB](249)

Abstract:
To counter the difficult problem on high hydrogen content in aluminum lithium alloys,the origins andexistence formations of hydrogen,and the effects of hydrogen on properties and fracture models are elaborated.It is believed that the main obstacle to limit property potentials and their applications in aerospace ismetallurgy qualities,especially for controlling of hydrogen content and hydrogen embrittlement.Reductionin hydrogen content will be substantive progress in aluminum lithium alloys research.Vacuum refining inliquid state and vacuum degassing in solid state are proposed to reduce hydrogen. Elementray problems encountered by vacuum degassing are suggested. Efforts will result in next generation of aluminum lithium alloys with improved strength and toughness.

1995 Vol. 15, No. 2