航空材料学报

DEFORMATION AND STRENGTHENING BEHAVIORS OF Al-5.5Mg-2.5Li-0.5Mn ALLOYS

Tian Baohui, Lu Zheng, Qiang Jun, Yan Minggao, Liu Bocao, Wei Bingchen

1998, 18(2): 1-7.

[Abstract](1476) [PDF 256KB](192)

Abstract:
Deformation and strengthening behaviors of Al-Mg-Li alloys with Mn additions were investigated. Serrated flow occurs during the deformation of alloys, the types of which can be related to the strain hardening exponent in certain stage of deformation.With addition of Mn in these alloys,it is found that the yield stress increases and the ductility decrease, accompanied by promotion of transgranular fracture.

EFFECT OF Li ADDITION ON THE PRECIPITATION BEHAVIOR AND MECHANICAL PROPERTIES OF Al-Mg-Si ALLOY

Wei Bingchen, Li Jianguo, Huang Zheng, Zhang Yonggang, Chen Changqi, Tian Baohui

1998, 18(2): 8-13.

[Abstract](1338) [PDF 465KB](210)

Abstract:
The effect of Li content on the precipitation behavior and mechanical properties of Al Mg Si alloy has been investigated. In Al Li Mg Si alloy, the ordered δ′phase became the predominant precipitate and no GP zones of Mg2Si are observed at peak aging condition. The 1.6%Li containing alloy shows slow aging reactions, limited hardening response and weak coplanar slip tendency, due to the small volume fraction of δ′phase. While the 2.6% addition produces a strong aging response, a higher σb at peak aging condition and extensive coplanar slip tendency under tensile stress, due to the formation of large amounts of homogeneously distributed δ′phase.

INFLUENCE OF VACUUM DEGASSING ON HYDROGEN CONTENT AND CHEMICAL COMPOSITION OF Al-Li ALLOY

Xiong Yancai, Lu Zheng

1998, 18(2): 14-17.

[Abstract](1440) [PDF 158KB](273)

Abstract:
To resolve the difficult problem of high hydrogen content and hydrogen embrittlement in Al-Li alloys,the influence of vacuum degassing on hydrogen content and chemical composition of 1420 alloy has been studied.The result lays a foundation of improving strengh and toughness on Al-Li alloys.

ON THE SENSITIVITY OF HYDROGEN EMBRITTLEMENT OF HIGH ALLOY ULTRA HIGH STRENGTH STEEL

Ling Bin, Zhong Ping, Zhao Zhengye

1998, 18(2): 18-24.

[Abstract](1446) [PDF 296KB](187)

Abstract:
The sensitivities of hydrogen embrittlement of 23NiCo steel with different heat treatment,i.e. as quenched,tempered at 200℃,450℃,482℃and 600℃ respectively,have been investigated. The results show that the fracture behavior of the 23NiCo steel was related with the shape and distribution of the austenite.It is thound that the resistance of the hydrogen embrittlement of the steel can be greatly increased by tempering at 480℃.

MICROSTRUCTURE OF THE NiAl(Fe) TiB₂ COMPOSITES FABRICATED BY REACTION COMPOCASTING

Wang Rongming, Tao Chunhu, Yan Minggao

1998, 18(2): 25-30.

[Abstract](1442) [PDF 227KB](141)

Abstract:
The effect on the room temperature compressive property and microstructure mechanism of Fe addition in the NiAl TiB2 composite fabricated by XD reaction compocasting. The room temperature compressive property of the composite improves to 20% with 25at% Fe addition. TEM and HREM results indicate that there exist β-Ni(Al,Fe), γ′-(Ni,Fe)3Al, TiB2 and a new Fe(Ni,Al,Ti) phase in composite. The Fe(Ni,Al,Ti) phase has a FCC crystal structure with lattice parameter a=1.068nm. The Fe(Ni,Al,Ti) phase bonds the matrix very well with no reaction product at the interface.

THE SPATIAL VARIATION OF THE MASS FLUX IN THE SPRAY FORMING PROCESS

Li Zhou, Mi Guofa, Zhang Guoqing, Zhang Zhihui, Liu Zhongwu, Tian Shifan

1998, 18(2): 31-35.

[Abstract](1420) [PDF 161KB](217)

Abstract:
Spray forming has been a newly emerging science and technology in the field of materials. In this paper, the spatial variation of the mass flux and deposition rate in the spray forming process was investigated, and the distribution function was established. It is found that the spray stream becomes centralized along with the increase of atomization pressure and the reduction of deposition distance.

A STUDY OF THE SPOT WELDING TECHNOLOGY AND PROPERTIES OF THE Ti-15-3 TITAINUM ALLOY

Hao Liping, Li Chaoguang

1998, 18(2): 36-40.

[Abstract](1479) [PDF 199KB](192)

Abstract:
In this paper, the spot welding technology and properties of the beta Ti-15-3 titanium alloy recently developed were investigated. The weldability of spot welding in comperison with the imported materials the experimental result yieled a reliable basis for the application of this alloys in local aircraft indutry.

IMPACT DAMAGE OF GLASS EVALUATED BY AN EQUIVALENT IMPACT METHOD

Bao Yiwang, Li Xiaorui, Jin Zongzhe

1998, 18(2): 41-46.

[Abstract](1311) [PDF 212KB](295)

Abstract:
Impact damage of solid particle to soda-lime glass was evaluated by means of an equivalent impact method. Freely falling body was adopted to imitate high speed impact of small particle and convincing results were obtained. It was revealed that, if the target and contact area are certain, equal impact kinetic energy will lead to the similar damage on the surface of target. Impact hammers with four different weights were used in the equivalent tests. The same impact force, similar Hertzian crack and equal residual strength were obtained in the tests.

THE RELIABILITY ANALYSIS OF COMPOSITE CONVOLUTION STRUCTURE BY NEUMANN STOCHASTIC FINITE ELEMENT

Chen ShunXiang, Hao Zhiming

1998, 18(2): 47-52.

[Abstract](1434) [PDF 391KB](258)

Abstract:
The paper has applied neumann series expansion to the monte-carlo stochastic finite element. So stiffness matrix was formed only one time during sampling. As a result, the calculate time of stochastic finite element was cut down greatly. Finally, the paper has calculated the reliability of composite convolution structure by use of monte carlo direct comparison method.

POLYMERS OBTAINED FROM BENZOCYCLOBUTENES

Huang Farong

1998, 18(2): 53-62.

[Abstract](4826) [PDF 373KB](1212)

Abstract:
Benzocyclobutene is a thermally activated precursor to the highly reactive intermediate orthoquinodimethane. The intermediate will react either with itself or dienophile in a Diels-Alder fashion. The chemical reaction principle for benzocyclobutene compounds, the properties and applications of polymers from benzocyclobutenes are reviewed in this paper. The tendency and prospect for the development of the materials are also discussed.

1998 Vol. 18, No. 2