航空材料学报

ON THE PHASE TRANSFORMATION IN SUPERALLOY GH169

Ling Bin, Zhong Bingwen, Yang Yurong, Liang Xuefeng, Sheng Biao

1994, 14(4): 1-7.

[Abstract](1466) [PDF 412KB](193)

Abstract:
The features and behavior of the transformation of the phases in Superalloy GH169 have been investigated using transmission electron microscopy(TEM)and the orientation relationship between γ"/γ,γ"/δ phase has been studied.

ON THE TENSILE FRACTURE BEHAVIOUR OF SINGLE CRYSTAL DD3 AT SLOW TENSILE RATE

Zhang Yuanhu, Cao Peng, Fang Wei, Yu Jinxin, Wu Zhongtang, Dai Xiuyan, Gui Zhonglou, Lao Yueling

1994, 14(4): 8-14.

[Abstract](1388) [PDF 424KB](188)

Abstract:
Single Crystal Superalloy DD3 was deformed in tension at slow strain rate at temperatures between ambient temperature and 1273K to investigate the mechanical properties.The anomalous temperature dependence of Young’s module at temperatures between room temperature and 873K, and the normal rela-tionship above 873K,were found.The results showed a plateau in yield strength between R. T. and 1033K(peak temperature).A significarit drop in strength occured above 1033K. The elongation was lowest atpeak temperature. Observation by SEM showed that tensile deformation for DD3 occured only in some prior slip systems. This priority led to the highly slip in homogenous nature. The fracture appearance was seento be ductile feature at all temperature although there were some quasi-cleavages in view of macro-observation under the peak temperature.

EFFECTS OF THERMAL EXPOSUREON MICROSTRUCTURE AND TENSILE PROPERTIES OF ALLOY 2324

Zheng Peng, Zheng Yuzhen, Wei Hui, Qian Yourong

1994, 14(4): 15-20.

[Abstract](1433) [PDF 310KB](201)

Abstract:
A study has been made to understand the microstructure,tensile properties of aluminum alloy 2324-T39 under thermal exposure at elevated temperature. Detailed optical and transmission electron microscopi-cal observations were used to analyse the intrinsic microstructural features of the T39 condition ,differencesin tensile properties of 2324- T39 and 2024-T351 are explicable from differences in micro structures.An attempt is made to discuss the influence of FTMT(Final Thermomechanical Treatment)on tensile propertiesand microstructure under thermal exposure.

EFFECT OF SPUTTERED NiCrAlY COATING ON OXIDATION RESISTANCE OF Ti₃Al INTERMETALLIC COMPOUND

Zeng Chaoliu, Wu Weisui, Zhu Shenglong

1994, 14(4): 21-25.

[Abstract](1449) [PDF 293KB](265)

Abstract:
Effect of sputtered NiCrAlY coating on oxidation of Ti3Al intermetallic compound in air at 850 and 950 ℃ has been investigated. The experimental results indicate that oxidation resistance of Ti3Al is ratherinferior,and a protective Al2O3 barrier couldn’t form on the alloy surface. The oxide scale easily spalls off.The sputtered NiCrAlY coation can improve oxidation resistance of Ti3Al by the formation of a protective Al2O3 scale. However,a three-layer diffusion zone between coating and base alloy was observed.

INFLUENCES OF QUENCHING METHOD ON MICROSTRUCTURE AND MECHINCAL PROPERTIES OF 16NiCo STEEL

Zhong Ping, Gu Baozhu

1994, 14(4): 26-31.

[Abstract](1335) [PDF 350KB](152)

Abstract:
In this paper,the influences of quenching temperature and cooling on the microstructure and proper-ties of 16NiCo steel were studied. The results show that with increasing the austenitizing temperature thevariations of properties of oil or air-blast quenching are similar At 800～830℃ quenching, the strengthreached to a maximum value. At 860℃ quenching,impact tougness is the highest. Comparing 860℃ oilquenching with 830℃ air-blast quenching,the impact toughness was improved fairly with a slight decreasein strength.

INVESTIGATION OF ALUMINIUM CONTENT IN Al/TiB₂ COMPOSITE TECHNOLOGY

Li Ying, Li Chunyu, Chai Shichang, Han Yafang, Xia Yang, Zhang Yue, Yuan Runzhang

1994, 14(4): 32-35.

[Abstract](1382) [PDF 239KB](156)

Abstract:
In this paper, the effect of different aluminium contents in Al,Ti,B mixed powder on formation of insinter reaction process,has been investigated by means of differential scanning calorimeter(DSC)and x-ray diffraction(XRD).The results show that:aluminium content in mixed powder is an important parame-ter.Although TiB2 particles can be formed at temperature 640℃ and 950℃,quantities of the TIB2 particlesare closely related to aluminium content.Mixed powder containing 50wt-% aluminium is considered as anoptimum composition.

TLP BONDING OF Al₂O₃ TO WX60 STELL AT LOWER TEMPERATURE IN AIR WITH RS ALLOY FOILS AS INSERT METAL

Zhai Yang, Ren JianLie, Zhuang Lijun

1994, 14(4): 36-40.

[Abstract](1454) [PDF 336KB](301)

Abstract:
In this paper,it has been succeeded in TLP-bonding of Al2O3 to WX60 steel at lower temperature inair with RS alloy foils as insert metal for the first time. The results thas shown that:The shear strengthand remelting temperature of joints were enhanced remarkably with RS alloy foils as insert metal. Themodification of joint was the most effective especially for using amorphous Cu50 Ti50 alloy foil. The maxshear strength and remelting temperature of joints were respectively 74MPa and 780℃. The effect of hold-ing time on the stength and remelting temperature of joints were obvious. The remelting temperature ofjoint was enhanced with the increase of holding time, whereas. It has an optimum range of holding timefor the strength of joint.

STUDY ON PARAMETERS MICROSTRUCTUE AND STRENGTHENING MECHANISM IN THE INERTIA FRICTION WELDING OF ALLOY GH4169

Liang Hai, Liu Xiaofang

1994, 14(4): 41-47.

[Abstract](1500) [PDF 397KB](245)

Abstract:
The microstructures and strengthening mechanisms in the inertia friction welded joints of Alloy GH4169 produced in different welding parameters were studied. It is found that the inertia friction weldingparameters for Alloy GH4169 were characterized by low spindle rotation speed, high axial pressure andlarge moment of inertia. Grain refinement occured with the formation of high density of intragranullar dis-location strucIture in the inertia welds. Most of Delta phase and all of γ"and γ’strengthening phases weredissolved in the central part of the inertia welds. Delta phase,γ"and γ’ strerigthening phases could,howev-er, exist in the HAZ of the inertia welds during inertia friction welding. Thus,grain refinement dislocationstructure and solid solution strengthening were involled in the as inertia welded Alloy GH4169,owing tothe thermornechanical processing from the inertia friction welding.

APPLICATION OF ARTIFICIAL NEURAL NETWORK TODSIGNING EXTERNAL CNILL FOR STEEL CASTING

Wang Gui, Huang Tianyou, Chen Zhongxing, Yu Zhenzon, Wang Lintao, Su Zhenqing, Wang Wenjun

1994, 14(4): 48-54.

[Abstract](1415) [PDF 417KB](207)

Abstract:
A new appproach using artificial neural network(ANN)techniques was used to establish the the nonlinear mapping relation of the casting geometry modulus, types and thickness of chill coating sand layer,chillthickness, solidification module. The result of application shows it is applieable.

SURFACE TREATMENT OF CARBON FIBERS AND INTERLAMINAR SHEAR STRENGTH OF COMPOSITES

He Fu, Yang Yonggang

1994, 14(4): 55-61.

[Abstract](1600) [PDF 461KB](459)

Abstract:
Carbon fibers reinforced plastics composites(CFRP)made from carbon fibers and matrix resin is amain form of utilization of carbon fibers. Practically the lowest limit value of interlaminar shear strength(ILSS)of CFRP needs 75MPa,but that of untreated carbon fibers is 50～ 65MPa,less than the lowestlimit value of ILSS of CFRP. After surface treated of carbon fibers,the value of ILSS of CFRP is greaterthan 80MP3, which meets the need of utilization of CFRP. Thus,the surface treatment of carbon fibers isa necessary and important procedure in the production line of carbon fibers.

1994 Vol. 14, No. 4