Z. Li
,
S.F. Tian
,
X.G. Zhao
,
Z.K. Liang
,
L.P. Ren
,
G.F.Mi and M.G. Yan(Bejing Institute of Aeronautical Materials
,
Beijing 100095
,
China Manuscript received 26 August 1996)
金属学报(英文版)
In this paper,part of the research and development work in the field of spray formed superalloys at BIAM of China is briefly summarized. With an experimental spray forming facility,whose melting capacity is suitable for making disk and columnar shaped integral-dense and clean Ni-base superalloy preforms with low oxygen content,fine grain, uniform chemistry and improved forgeability, a series of Ni-base superalloys have been spray atomized and deposited, among which three alloys have been chosen for microstructural and mechanical properties evaluation.
关键词:
:spray forming
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null
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null
WANG Shuncai LI Chunzhi YAN Minggao Institute of Aeronautical Materials
,
Beijing
,
China BIAN Weimin Northeast Institute of Technology
,
Shenyang
,
China WANG Shuncai Graduated Student
,
Institute of Aeronautical Materials
,
Beijing 100095
,
China
金属学报(英文版)
X-ray microanalysis,convergent beam electron diffraction(CBD)and selected area electron diffraction(SAD)studies on the structures and compositions of the constituent phases in 2024 series Al alloys have been conducted.Partial substitution of alloying elements is found to occur in all the constituent phases,which cause small deviations from the stoichiometric com- positions reported in these ternary compounds.The dominant phase is α-Al_(12)(FeMn)_3Si which has a body center cubic crystal structure with the Im■ space group and a=1.25 nm.The next dominant phase is Cu_2FeAl_7 which has a primitive tetragonal crystal structure with the P4/mnc space group and a=0.6336 nm,c=1.487 nm.The minor phase is α'-Al_(12)Fe_3Si hav- ing α primitive cubic crystal structure with the Pm■ space group and α=1.27 nm.
关键词:
Al alloy
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null
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null
Liang ZHEN Yuexian CUI Dezhuang YANG Department of Materials Science
,
Harbin Institute of Technology
,
Harbin
,
150006
,
ChinaShenglong DAI Guifu YU Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China
材料科学技术（英文）
The formation of precipitation free zone (PFZ) and its effect in a RSP AI-Li alloy has been studied. The results show that PFZ is easy to form when aged at 190℃,but there is no equilibrium phase on grain boundaries.The growth of PFZ in the alloy is different from that in conventional AI-Li alloys, The effect of PFZ is of great importance because of its large volume fraction in the alloy.It offsets the beneficial effect of RSP,and is thought to be an important factor that leads to the poor toughness and low ductility of RSP AI-Li alloy sheet.
关键词:
precipitation free zone
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null
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null
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null
MAO Jian YANG Wanhong WANG Wuxiang ZOU Jinwen ZHOU Ruifa Beijing Institute of Aeronautical Materials
,
Beijing
,
China MAO Jian
,
senior engineer
,
Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China
金属学报(英文版)
Nature of PPB precipitation of P/M Rene'95 and its effects on mechanical properties,frac- ture morphology and microfracture characteristics are discussed.Dense PPB precipitates make the boundaries brittle and lower the plasticity of the alloy.Fracture path is along the boundaries of particles.As PPB parameter increases,the interfaces between particles are strengthened.The fracture mode is changed from interparticle to transparticle.As a result,the plasticity at high temperatures and stress rupture life of the alloy are improved.
关键词:
Rene'95
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null
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null
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null
HE Jinrui LU Younian WANG Qingsui SU Hansheng ZHANG Xueduo WU Mingchang ZHU Qiao Beijing Institute of Aeronautical Materials
,
Beijing
,
China P.O.No.81—23
,
Beijing 100095
,
China
金属学报(英文版)
The time-dependent fatigue and its micromechanism of superalloy GH169 at 650℃ have been studied.Under the same stress and duration,its cyclic life in Ar is shorter than that in air.The damage mechanism is mainly of the interaction between high temperature oxidation and fa- tigue.The fracture surface of GH169 specimen oxidized at 650℃ in air is revealed to be cov- ered with a dense and even oxide film,but in Ar,with uncontinuous oxide particles.As the time prolonged,the Cr_2O_3 content in the surface oxides increases in air and decreases in Ar.
关键词:
superalloy GH169
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null
,
null
,
null
F.Lu
,
W.Y.Shen
,
J.G. Li and W.D. Zhen(Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China Manuscript received 26 August 1996)
金属学报(英文版)
The electrochemical approach was used to show the nature of the galvanic corrosion when graphite epoxy composite materials(GECM)were coupled to LY12CZ aluminum alloy. An open circuit potential difference of one volt was obtained in 3.5% NaCl solution between GECM and LY12CZ. Corrosion current data (zero impedance technique) indicated that there was serious corrosion at GECM/LY12CZ couple.When GECM/LY12CZ couples were exposed to ASTM salt spray and alternate immersion condition, fiber glass cloth and H06-2 epoxy primer paint were effective methods for preventing galvanic corrosion.The slow strain rate test (SSRT) showed that GECM increased the LY12CZ stress corrosion crack growth rate.
关键词:
:galvanic corrosion
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null
LUO Zhiping ZHANG Shaoqing Institute of Aeronautical Materials
,
Beijing
,
China LUO Zhiping
,
doctorate student P.O.Box 81-4
,
Beijing 100095
,
China
金属学报(英文版)
Microstructural studies have been made on the Mg-0.54Zr,Mg-5.68Zn and Mg-5.65Zn-0.50Zr alloys in the as-cast and homogenized states.The lenticular plates of {012}twins were found in three alloys.After homogenization,ZrH_2 phase formed in the Mg-0.54Zr alloy.The Mg_7Zn_3 phase of cubic structure with a=1.417 nm distributes at the grain boundaries of the Mg-5.68Zn alloy in the as-cast state and after homogenization,the Mg_7Zn_3 phase dissolves and the MgZn_2 phase occurs.The as-cast Mg-5.65Zn-0.50Zr al- loy consists of MgZn_3 phase and Zn-Zr compounds.After homogenization,the dispersed acicular MgZn_2 phase may precipitate.
关键词:
Mg-Zn-Zr alloy
,
null
,
null
S.K.He
,
G.S. Wang and S.N. Wang(Beijing institute of Aeronautical Materials
,
Beijing 100095
,
China Manuscript received 26 August 1996)
金属学报(英文版)
Influences of sulphureous impurity and micro-shrinkage on hydrogen assisted cracking (HAC) and fracture behavior of the super-strength low-alloy steel 40CrMnSzMo VA have been studied in this paper.By way of scanning electron microfractography (SEM)and electron probe microanalyser to investigate the fractography of material constantly strained to failure, it was found that the microscopic segregation of sulphureous impurity and micro-shrinkage not only increased strongly the susceptibility to hydrongen embrittlement (HE), but also made the HAC to initiate preferably in such regions with the assistant of stress induced diffusion of hydrogen. The microscopic observation revealed that the steel has commonly intergranular (IG) and quasi-cleavage (QC)features around the segregation of sulphureous impurity and micro-shrinkage for their strong effects of irreversible traps for hydrogen.
关键词:
:micro-shrinkage
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null
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null
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null
