航空材料学报

THE EFFECT OF SOLUTION TEMPERATURE ON MICROSTRUCTURE AND PROPERTIES OF SINGLE CRYSTAL NICKEL BASE SUPERALLOY

Xue Hongmei, Yang Zhenfan, Li Dingxiu, Sun Jiahua

1984, 4(2): 1-6.

[Abstract](1184) [PDF 3710KB](75)

Abstract:
In this paper the effect of solution heat treatment temperature on the microstructure and properties of single crystal alloy Ni-5Cr-1Mo-10.5W-3.3Ta-5.8A1-1.2jTi was examined.Solution heat treatment studies showed that the amount of as-cast coarse y phase gradually reduced and the amount of fine y phase increased with increased solution temperature within the range of 1240C to 1320℃.The increase of the amount of fine y phase is due to the gradual solutioning of coarse yphase and subsequent reprecipitation of fine yf phase during cooling.The 760℃, 1050℃ tensile strength and 1050C creep-rupture life of this alloy increased significantly with increased amount of fine yphase.

EFFECT OF CRYSTAL ORIENTATION ON FATIGUE PROPERT工ES OF THE NICKEL-BASE SINGLE CRYSTAL SUPERALLOY DD3

Wang Qingsui, Zhang Guohuan, LiuZeyao

1984, 4(2): 7-14.

[Abstract](1255) [PDF 4431KB](101)

Abstract:
The effects of crystal orientation on low cycle and thermal-mechanical cycle fatigue properties of the nickel-base cast single crystal superalloy DD3 were investigated.The orientation of single crystal specimens grown by seed cry-stal is closed to the orientation [001]，[011],[111]and [137] in the stan-lord oriented triangle of tereographic projection, respectively.It was con-cIuded that (1)the[111]oriented specimen has a little higher low cyclefatigue property than other oriented specimens; (2) the influence of crystal orientation on the low cycle fatigueof DD3 single crystal superalloy,in general，is not obvious.It was found that the effect of thermal-mechanical cycle on fatigue property of DD3 superalloy is much larger than that of low cycle.Lastly, the changes of fatigue property were discussed on the basis of fractographp.

EFFECTIVE GRAIN AND TOUGHNESS IN STEEL CONTAINING SILICON

Zhong Bingwen, Song Yuwen

1984, 4(2): 15-19.

[Abstract](1170) [PDF 2644KB](74)

Abstract:
Contraticlorp toughness results measured on Kic and U-notch test pieces after isothermal transformation at 180℃(or 190℃)。nd 3000℃ is rationalized intermsg raina differing toughness is response of the microstructure.The effect of effective greater than other microstructure factors

THE EFFECT OF INTERFACIAL BONDING ONTHE MECHANIC AL PROPERTIES OF CARBON FIBER COMPOSITES

Jin Yongfang, Lan Liwen, Lei Weiyuan

1984, 4(2): 20-24.

[Abstract](1224) [PDF 3044KB](80)

Abstract:
The effect of surface treatment levels of carbon fiber on the mechanical pro-perties of composite was investigated in this report.Experimantal results showed that the interla minar shear strength，transverse tensil strength of unidirectiona composites were increased and the impact toughness was decreased with incre-asing the treatment level of carbon fiber, There is a maximum value of the delamination fracture toughness of unidirectional composites in the adequate surface treatment level, after which the value will degrade. The failure modes of fracture surface and the crack extensiones under the different condition were observed by scanning electron microscope.T he effect of the interfacial adhesion and the crack extensiones on the mechanical proper-lies of CFRP was described.

FRACTURE CHARACTERISTICS AND DUCTILITY OF TIG WELDED JOINTS OF Ti-6A1-4V ALLOY SHEET DURING BENDING TEST

Tang linrong, Li Chaoguang, Sun Shiying, Zhang Yansheng

1984, 4(2): 25-28.

[Abstract](1192) [PDF 2447KB](71)

Abstract:
This paper describes the results of bending test at roo m tem perature forTIG welded joints of Ti-gAl-.lV alloy sheet using a special bending test app-aratus developed in the authors laboratory.The dynamic processes of the initiation and propagation of cracks during bending were。directly observed and photographed by- a stereo microscope.The oxide layers of the weld sur-face were analyzed by Auger electron spectroscope.人nd the microstructure of the joints was observed under optical and electron microscopes.The test re-suits show that the effect of the microstructure of welded joints on bending ductility is greater than that of oxidation degree of the weld surface.The microstructure and the bending ductility of the weld can be improved by vacuum annealing at 730℃/6hr.

RELATIONSHIP BETWEEN SHOT FEENING SURFACE STRAIN LAYER AND FATIGUE STRENGTH OF HIGHSTRENGTH ALUMINIUM ALLOY

Wang Renzhi, Li Xiangbin, Wu Heng

1984, 4(2): 29-35.

[Abstract](1137) [PDF 4126KB](60)

Abstract:
The relationship between fatigue behavior and residual stresses and plastic deformed microstructures in the surface strain layers of highstrength aluminium alloy has been investigated.lt has been shown that the stress and microstructure strengthening are two factors improving fatigue strength and that the microstructure strengthening factor plays main role to improve fatigue behavior under the high alternating stress position of S-N curve but the main contribution to the fatigue behavior near the fatigue limit is the stress strengthening factor. There is a optimum residual stress field induced by shot peening for highstrength aluminium alloy and the maximum optimum compressive residual stress in the field is (a)o p s- a.

PREOXIDIZING EFFECT OF ALUMINIUM-SILICON COATINGS

Mo Longsheng, yang Zhonglin

1984, 4(2): 36-43.

[Abstract](1259) [PDF 4453KB](67)

Abstract:
It has been found that a simple preoxidizing treatment added between two processes of coat treatment and diffusion treatment increased considerably hot corrosion resistance of ASL-3 type coatings, but did not damage any mechani-cal properties of coating}substrate system during the researching hot corrosion behavior of a series of ASL coatings.It has been indicated that the preoxidizing treatment led to form a very dense and thin oxide film containing relatively high Aluminium and silicon on the surface of coating by SEM, EPMA and IMA analyses，The silicon that present within the film supplies superior hot corrosion resistance for the coating, The results of tests show that the hot corrosion resistance of AI-Si coatings is closely concered with the surface states of the coatings, In addition, the effects of preoxidizing treatment arc very different for various diffusion-type AI-Si coat-ings used different processes.

EFFECT OF COLD EXPAr}SION ON FATIGUE CRACK INITIATION AND GROWTH BEHAVIOR AT FASTENER HOLES IN A NIGH STREN GTH STEEL

Su XiaoYan, GuMingda, Yan Minggao

1984, 4(2): 44-50.

[Abstract](1205) [PDF 4075KB](77)

Abstract:
In this paper，the effect of culd expansion process on the fatigue crack initiation and growth behavior at fastener holes of 30CrMnSiNi2A plate speci-mens under constant amplitude cyclic loading has been investigated, The infor-matien of the crack growth and initation was obtained by A.C.potential me-thod.The experimental results indicted that the cold expansion can significantly extend the fatigue life and the degree of improvement is increased with dec-rearing stress level applied, However, only the fatigue crack growth life was noticeably affecteJ and no obvious effect was observed on the fatigue crack initiation life under the present process of cold working.

THE ANISOTROPY OF SINGLE CRYSTAL OF A NICKEL BASE SUPERALLOY INVESTIGATED BY ULTRASONIC WAVES

Wen Zhongyuan, Li Jiawei, Zhang Guohuan

1984, 4(2): 51-57.

[Abstract](1216) [PDF 3974KB](98)

Abstract:
The purpose of this work was to investigate the anisotropy of single crystal of a nickel base superalloy by ultrasonic waves.The anisotropy of surface wave velocity and primary back echo amplitude was tested on quasi-(001) surface along the directions with p-360' from[ 001].The compressional and shear waves have different velocities andor different relative attenuation factors in different propagation directions.The elastic constants of the tested alloy were calculated from compressional wave velocity and the ones of shear wave in pure m odas according to the special solutions of christoffel equation.

SOME CHARACTERISTICS OF MATERIAL STRENGTH OF GAS TURBINE TO SERVICE ON THE GROUND

Zhang Xingan, He Jinrui

1984, 4(2): 58-65.

[Abstract](1161) [PDF 4936KB](81)

Abstract:
jn this paper characteristics of failure of gas turbines are discussed According to different service conditions in air and on the ground it is pro-posed that creep and the da m age caused by Corrosion become the lead ing factoys affecting the service life of gas turbines which service on the ground.It is also proposed that the following work should be done such as life predic-tion, study of properties of creep rupture，corrosion effect on failure and the development of new coating meterials.

TIDE CHARACTERIS"TICS OF ISOTHERMAL FORGING OF TITAN工UM ALLOY

Liu Jianyu, Zhang Beilian, Wang Xianmin, Jiang Cuidi

1984, 4(2): 66-70.

[Abstract](1150) [PDF 3010KB](62)

Abstract:

EDDY CURRENT TESTING FOR NDT OF COMPOSITE MATERIALS

Ma Zhenya

1984, 4(2): 71-75.

[Abstract](1187) [PDF 2730KB](64)

Abstract:

THE CURRENT PROGRESS IN A1-Cu-Li ALLOYS

Feng Weiyi

1984, 4(2): 76-77.

[Abstract](1200) [PDF 569KB](60)

Abstract:

1984 Vol. 4, No. 2