航空材料学报

The Microstructure and High Temperature Strength of γ/γ' Systerm Directionally Solidfild Eutectic Alloys

Zhang Rongwu, Minoru Hemuto, Hajime Suto

1984, 4(1): 1-6.

[Abstract](1193) [PDF 4141KB](79)

Abstract:
The Paper expounds that is develop researchs in Ni-Al-Ti system /' eutectic alloys with f.c.c type crystal place.The researchs have showed what there is eutectic line in Ni-Al-Ti system diagram, and both of ' and phases can grow to directionally solidified / eutectic structure well.The distance S between and ' phases to solidified speed r satisfys following form: S/ r.The reseachs have showed too that /' system directionally solidified eutectic alloys have good plasticity and high temperature strength.The place(100)of /' phases slopes from growing direction to 5~15 degree.At directionally solidified and aged condition the strutures of alloys consist of both of and ' phases.The dislocation structure of sampie ruptured and dislocation of boundary at /' phases were studied.The room press deformation occurs to (111)110 closed-arrangce direction.

An Investigation of Directionally Solidified Superalloy DZ22

Wang Luobao, Chen Rongzhang, Wang Yuping

1984, 4(1): 7-13.

[Abstract](1230) [PDF 4308KB](73)

Abstract:
In this paper the composition, mechanical properties, microstructure and the processes for melting and casting of DZ22, a directionally solidified superalloy for gas turbines, has been described.The research results show that alloy DZ22 exhibits rather high mechanical properties at both intermediate and high temperature, and it is comparable with alloy PWA1422 which is well-known DS superalloy developed by Pratt-Whetney Aircraft Co.Alloy DZ22 also showed excellent castability.The alloy has been used to product hundred of the order of blades.The test result of high temperature gas shock has also been listed in the paper.

Incipient Melting and Control of DS Nicket Base Superalloy DZ22

Zheng Yunrong

1984, 4(1): 14-20.

[Abstract](1232) [PDF 5118KB](76)

Abstract:
The peak of 1135~1160℃ appeared at DTA curve during heating is the melting range of Ni5Hf phase when the volume of Ni5Hf is greater then 1.0 Vol.％.Ni5Hf may induce the incipient melting of Hf-beariny cast nickel-base superalloy.A distinct segregation of Ni5Hf between the top and the bottom of the directionally solidified ingots was noticed, and their sensitivities to incipient melting are quite different consequently.The more Ni5Hf phases were formed in the low-carbon or carbon-free alloy DZ22 and promoted incipient melting of alloy. By means of pretreatment at 1150℃ for 8h, Ni5Hf-phase can be eliminated and therefore the temperature of final solid-solution treatment may rise about 50℃.After this treatment, homogenizing effect was obtained obviously and stress-rupture properties of alloy at 1040℃ have been increased further.

An Investigation of Notch Sensitivity of GH33A Alloy

Zhou Ruifa, Deng Bo

1984, 4(1): 21-27.

[Abstract](1193) [PDF 4942KB](76)

Abstract:
In present paper has investigated the relationship between the service temperature(T)and stress()and life()at the different notch radius of GH33A nickel-base alloy.It is given out the dynamic factor(Sb)of temperature and stress for activational notch sensitivity, as follows; Sb=P.lg, P=(16+1.51g) Experimental results showed that it is not notch sensitivity under the condition of Sb

Monitoring Nugget Size by Welding Parameter Integration

Liu Xiaofang, Bao Xuewu, Zhang Xinzhong, Yu Shengke

1984, 4(1): 28-34.

[Abstract](1178) [PDF 4899KB](62)

Abstract:
This paper describes the research work and applications of monitoring technique of nugget size in spot welding by Ivdt integration method.The variations of nugget sizes caused by fluciuatsons in current,volatge, electrode force and shunt current etc can be shown by means of monitoring the quantity of energy afforded to each nugget. It has been proved that this method is convenient, efficient and appropriate to various fields with sufficient reliability.

Properties of Mixed Resins and Their Composites.

Yuan Zhenghua, H.Twardy

1984, 4(1): 35-42.

[Abstract](1216) [PDF 4959KB](58)

Abstract:
Composite materials for the next generation of aircraft must have a high temperature stability and high elongation at break. For application requirement of composites in aircraft, the only way is now to optimize existing mixtures with high temperature stability and high break elongation.The properties of g types of mixtures for MY720 and LY556 resins and their composites with three types of carbon fibres(T300, ST-1-7 and HM45) respectively were tested in this work.The preparation for pure resin and composite specimens are described.The obtained results for temporature stability, the elongation at break and tensile strength of resin mixtures are presented. And the tested results for composites with three types of carbon fibres recpectively are discussed in detail.

A Cycle J Integral Formula for CT Specimen.

Xie Jizhou, Liu Shaolun

1984, 4(1): 43-50.

[Abstract](1220) [PDF 4939KB](71)

Abstract:
In this paper a cycle J integral formula for CT-Specimen was improved as follows： J=2/Bb(1U+2P )+2Ue/Bb{一1.2025a/W+0.6233 0.3a/W0.53 一0.02Sin[/0.23(a/W一0.53)] 0.53＜a/W0.95 This formula is applicable to the crack propagation range of 0.3a/W0.95. In comparison with the same kinds of cycle J integral formula, the application range of the above expression is enlarged, and its precision is also increased to a certain degree

An Investigation on the FGH95 Superalloy Particle Size Distribution Function

Yu Kelan, Gong Zhanghan

1984, 4(1): 51-56.

[Abstract](1175) [PDF 4011KB](74)

Abstract:
The purpose of this Paper is discussing mainly the argon atomization FGH95 superalloy particle size distribution function.FGH95 powder of some types are tested and the results are regressively calculated. lts defined that the particle size distribution funefion is the negative exponential model. Its assumed that the statistic for comparison the slops of linear regression eguations is used to inspect the difference between two particle size distribution curves. Under the given conditions, i,e, the distribution functions for both curves are the same, and in the same statistical range, it's proved that this assume is feasible.

Mechanisms of Fatigue Crack Propaction and Their Enginering Application to some Structural Materials

Yan Minggao

1984, 4(1): 57-76.

[Abstract](1264) [PDF 13371KB](60)

Abstract:
A brief review of recent works on the fatigue crack propagation behavior and their applications to some aircraft Al-,Ti-alloys and high strength steels conducted in the Institute of Aeronautical Mo terials, Beijing is presented.The change of microscopic morphology and mechanisms of FCP at different propagation stages, especially in the initiation stage, are descrihed. A general analytical expression for calculating fatigue threshold values of common metals and alloys is proposed. An evaluation of four current retardation models on their ability to prediet fatigue life of Ti-6Al-4V alloy under tensile overloading has been made.Some modifications of the willenborg and Maarse models and their applications to the life prediction of Al-and Ti-alloys were investigated. It is recognized tnat the ability to predict life of the present modified Maarse model is improved obviously under tensile overloading and spectrum loadings. The effect of microstructures, stress ratios, surface conditions and envionments on fatigue crack propagation behaviors of some aircraft structural rmaterials is discussed.

A Study of Regression Analysis of Fatigue Crack Growth Rate Data in Stage I

Zhao Wei, Ding Chuangfu, Gu Mingda

1984, 4(1): 77-80.

[Abstract](1248) [PDF 13259KB](38)

Abstract:

1984 Vol. 4, No. 1