航空材料学报

Microstructure and mechanical properties of a new kind of precipitation-hardenable martensitic stainless steel with ultra-high strength and high toughness

LI Zhi, ZHI Min-xue, LIU Tian-qi, ZHAO Zhen-ye

2000, 20(3): 1-5.

[Abstract](1199) [PDF 843KB](497)

Abstract:
On the basis of analysis of high strength precipitation-hardenable martensitic stainless steel and high-alloy-ultra-high-strength steel available in aeronautical field, a new kind of precipitation-hardenable martensitic stainless steel with ultra high strength and high toughness has been developed. Its mechanical properties reaches the level σb≥1800MPa, δ5≥15%,KⅠC≥100MPam1/2, which has satisfied the design requirement.

A study on microstructure and mechanical properties of GH909 after long time ageing

ZHAO Yu-xin, ZHANG Shao-wei

2000, 20(3): 6-10.

[Abstract](1119) [PDF 1263KB](230)

Abstract:
The microstructure and mechanical properties of superalloy GH909 after long time exposure up to 2000h at 650℃ are studied. It is indicated that after long time exposure at 650℃ the quantity of ε/ε″acicular phase increases and their sizes coarsen, the quantity of γ′phase increases, the tensile strength of the alloy reduces and ductility increases, at 650℃/510MPa, notch rupture life increases. The microstructure and mechanical properties of the alloy after long time exposure up to 2000h at 650℃ are still basically stable, the alloy GH909 has good combination properties.

Effect of Re on coarsening behavior of γ′ phase in Ni-base superalloy

MA Shu-wei, LI Jia-rong, HOU shu-e, ZENG Qiang, ZHENG Yun-rong, YAN Ming-gao

2000, 20(3): 11-15.

[Abstract](1088) [PDF 1220KB](505)

Abstract:
The coarsening behaviors of γ′ at 1100℃ have been investigated in DD6 single crystal superalloys with different Re additions,i.e.DD6+0Re, DD6+1Re, DD6+2Re wt%. The three alloys were annealed at different time, i.e. 50, 24, 12, 6, 3, 1, 0.5h. The mean sizes of γ′ in different alloys at different annealed time were analyzed by SEM and statistic methods. The distribution and kinetic curve of γ′ have been obtained in this paper. The results showed that the addition of Re can effectively decrease the kinetics for coarsening of γ′ phase.

High temperature oxidation behavior of Ti-Cr alloys

HUANG Xu, SUN Fu-sheng, WANG Bao, LI Zhen-xi, CAO Chun-xiao

2000, 20(3): 16-20.

[Abstract](1167) [PDF 953KB](232)

Abstract:
Cyclical oxidation experiments for Ti-11Cr,Ti-13Cr,Ti-15Cr alloys were carried out in air at 600℃ and 800℃.The results showed that at the same temperature,with Cr content increasing,the weight gain decreases.For the same alloy,the weight gain increases with increasing temperature.The grain size of oxide formed on Ti-Cr alloy containing higer Cr is smaller than that formed on Ti-Cr alloy whose Cr content is lower.However,the adhesiveness and resistance to cracking or spalling turn out better with higher Cr content.

Effect of Ru addition on high temperature oxidation behavior of cast Ti-47Al alloy

WANG Xiao-ping, ZHENG Yun-rong, LI Jian-ping

2000, 20(3): 21-26.

[Abstract](1123) [PDF 976KB](280)

Abstract:
The effect of 1at%Ru addition on the high temperature isothermal oxidation behavior (800℃, 900℃) of cast Ti-47Al alloy was studied by static interrupted oxidation method in air. The results show that the oxidation kinetics of both alloys approximately followed parabolic law at 800℃, whereas, their oxidation kinetics changed to follow linear law at 900℃. The oxidation scales formed at 800℃ were consisted of two layers of Al2O3+TiO2/Al2O3+TiO2+TiN (from outer to inner); the oxidation scales formed at 900℃ were consisted of three layers, TiO2/Al2O3/Al2O3+TiO2, but the penultimate continuous Al2O3 layer was not existed in Ti-47Al-1Ru alloy. The 1at% Ru addition has an obviously deleterious effect on its oxidation resistance of cast Ti-47Al alloy at 900℃.

Effect of Nd-rich second phase particles on fracture behaviors of a near-α titanium alloy

ZHU Zhi-shou, MA Ji-min, GAO Yang, CAO Chun-xiao, YAN Ming-gao

2000, 20(3): 27-32.

[Abstract](1058) [PDF 279KB](320)

Abstract:
By means of in-situ SEM tensile deformation and rod sample deformation tests, the effect of brittle fracture of Nd-rich second phase particles on the fracture behaviors of a near α titanium alloy has been investigated. The results show that the formation of Nd-rich second phase particles can improve ductility of this alloy and reduce tensile strength to some extent. And early brittle fracture of particles has no detrimental effect on plastic deformation behaviors due to the beneficial microstructure changes caused by formation of Nd-rich particles.

Fatigue small crack behavior of Ti-6Al-4V alloy

HU Ben-run, WU Xue-ren, DING Chuan-fu

2000, 20(3): 33-37.

[Abstract](1213) [PDF 646KB](345)

Abstract:
Small crack growth tests were carried out on Ti-6Al4-V forge alloy with two kinds of microstructures prepared by differenTheat treatments. Small and long fatigue crack growth rates, da/dN, are presented against the stress intensity range, ΔK. The results showed the classic small crack effects for the both kinds of microstructures under constant amplitude loading and that the small crack effect was more pronounced at R=-1. Compared the small crack effects of two kinds of microstructures at the same stress ratio, R. It shows that the small cracks effects for both microstructures are same at R=-1. However, at R=0, it is show more pronounced small crack effect for the microstructure with finer grain size.

Grain refining processes and microstructure evolution of Ti-47Al-2Cr-1Nb alloy

HUANG Zhao-hui, WANG Shu-yun, LI Yuan-chun

2000, 20(3): 38-43.

[Abstract](1121) [PDF 927KB](236)

Abstract:
The grain refining processes by isothermal compression and heat treatment, as well as microstructure evolution of the Ti-47Al-2Cr-1Nb (at%) alloy, were investigated in this paper. The coarse lamellae of as casting TiAl alloy are broken by double isothermal compression (reduction in height above 70%) and refined after heat treatment, resulting in fine and homogeneous equiaxed γ grains. Forged microstructures indicate that dynamic recrystallization has occurred during isothermal compression and caused the flow softening.

Thermal analysis of aluminum cast alloy

WANG Ying-jie, JIA Pan-jiang, YAO Wei-bin

2000, 20(3): 44-48.

[Abstract](1168) [PDF 667KB](468)

Abstract:
Thermal analysis is mainly used to study the microstructure including grain refining and eutectic structure of aluminum cast alloy in this paper. It is found that the parameters of ΔTl and tR are effective to indicate the grain refining of the casting, and two parameters of ΔTE and te can be used to forecast the grade of the eutectic structure. The correspondent data to the AFS standard of grain size and eutectic silicon have been worked out.

Modification of fretting properties by ion implantation

WANG Er-min, WANG Xiao-zhen, HE An-li, ZHANG Tong-he, LIANG Hong

2000, 20(3): 49-55.

[Abstract](1090) [PDF 756KB](215)

Abstract:
So far, fretting induced failures in electrical contact is an important subject, but has not been paid much attention in experimental investigations. In order to improve the assistance to oxidation and wear of electrical contact materials, a investigation has been made of the ion implantation of AgCu10 alloy. It is indicated that the implantation of yttrium remarkably inhibits the formation of abrasive particles and depresses the migration of metals. Also it is found that the implantation of yttrium can effectively resist the surfacial oxidation. As a result, the ion implantation can substantially improve the resistance to metal removal and corrosion of the AgCu10 alloy, enhancing the fretting properties and reducing the contact resistance of the alloy.

Effect of MCrAlX overlay coating on mechanical properties of Ni₃Al based alloy IC6

LI Shu-suo, XIAO Cheng-bo, LI Jian-ping, HAN Ya-fang

2000, 20(3): 56-60.

[Abstract](1157) [PDF 210KB](218)

Abstract:
The NiCrAlY,NiCoCrAlY and NiCoCrAlYHf overlay coatings were deposited on Ni3Al based alloy IC6 used by arc PVD method, as well the tensile properties at room temperature and the stress rupture lives of coated and uncoated alloy IC6 were tested. The experiment results show that the three MCrAlX overlay coatings only make an effect on the tensile properties insignificantly, and the NiCoCrAlY and NiCoCrAlYHf coating also have no evident effect on the stress rupture lives, but the NiCrAlY coating make the stress rupture life of alloy IC6 decrease obviously. We studied the microstructure and chemical composition of the NiCrAlY coating before and after the stress rupture test by SEM and EPMA. There is regular-lumped AlN phase appearing in the coating, so it maybe the AlN phase results in the decreasing of the stress rupture life of alloy IC6.

Characteristic of microstructure and high-temperature properties of sputtered coatings

GAO Yang, CHEN Meng-cheng, LI Jian-ping, RU Ji-lai, WANG Ren-zhi

2000, 20(3): 61-66.

[Abstract](1203) [PDF 794KB](283)

Abstract:
kW RF magnetron sputtering unit gained zirconia ceramic coatings on hollow turbine blades and vanes, which had been deposited NiCrAlY bond coat by cathodic arc deposition.The microstructure and phase composition were investigated using electron probe microanalysis (EPMA) and X-ray diffraction(XRD).NiCrAlY coating surface was treated by shot peening, the effects of heat treatment on the residual stress are presented. No degradation occurred to RF ceramic coatings after 100 hours high temperature oxidation at 1100℃ and 500 thermal cycles at 1150℃ for 2 min, air cooling.

Relative density and gas content in spray formed superalloys

LI Zhou, ZHANG Guo-qing, ZHANG Zhi-hui, LIU Zhong-wu, TIAN Shi-fan, YAN Ming-gao

2000, 20(3): 67-72.

[Abstract](1253) [PDF 815KB](176)

Abstract:
One of the most common defects found in spray deposited materials is porosity, which may degrade their mechanical properties especially at elevated temperature, and also affect the secondary working to convert these preforms to the final parts. The size and distribution of pores, the relative density, and gas content of spray formed superalloys and the formation mechanisms of porosity were investigated in this paper. The results indicate that the relative density of deposited superalloys is related closely to the gas content and solidification condition, and the relative densities in edge and finally solidified region are lower. However, the relative density of nitrogen atomized and deposited preform may be greater than 99%, which is higher than that of the argon atomized and deposited preform. Moreover, the relative density of preform can be improved through subsequent processing such as HIP.

Investigation of atmosphere corrosion environment characteristic at Hainan Wanning

QI Feng-yu

2000, 20(3): 73-77.

[Abstract](1096) [PDF 595KB](288)

Abstract:
It is summarized the data of atmosphere corrosions at Hainan Wanning by ACM for one year, it was made analysis of the environment factors and atmosphere corrosions, and the mathematical calculation. The correlativity of environment factors and atmosphere corrosions at Hainan Wanning was obtained. Due to the climate of Hainan Wanning, the atmosphere corrosion is continues affected by the hot and humid climate, however, the atmosphere corrosion is not serious, because the air pollution is not serious in this area.

Study of electroplating technology of Ag-Sb alloy coating

TANG Zhi-hui, LI Bin, ZHANG Xiao-yun, LIU Ming-hui, SUN Zhi-hua

2000, 20(3): 78-83.

[Abstract](1164) [PDF 791KB](284)

Abstract:
The effects of solution components for silver-stibnic alloy electroplating and operative condition on stibnic content and depositing velocity of plating had been studied. The results indicate that, (1) stibnic content of plating is in direct proportion to current density,potassium cyanide content and antimony potassium tartrate content,(2) stibnic content of plating is in inverse proportion to potassium hydroxide content,(3)temperature and sodium-potassium tartrate content is unaffected by stibnic content of plating,(4)depositing velocity of plating is determined by current density and unaffected by solution components. Solution components and operative condition were determined. The properties of plating had been examined overall.

Effect of netty pipe state on ignition property of catalytic igniter

GAO Shan, CHENG Yi-fei, TAO Chun-hu, TAN Hao-yuan, DONG Kang, MA De-liang, LI Wen-lin

2000, 20(3): 84-88.

[Abstract](1156) [PDF 230KB](190)

Abstract:
The catalytic netty pipe is the key component of the catalytic igniter in the combustion tube of aero-engine.This paper presents the effect of surfacial state of netty pipe on the ignition property of catalytic igniter.The results have shown that the porosity of the plating have an effect on the ignition property of catalytic netty pipe and principal effective factor is the purity of surface layer.

TEM study of borides formed at TLP bonding interface

XIE Yong-hui, LIU Xiao-fang, MAO Wei, LI Xiao-hong, YAN Ming-gao

2000, 20(3): 89-93.

[Abstract](1085) [PDF 693KB](164)

Abstract:
When joining IC-6 superalloy using nickel based filler metals with boron as melting-point depressant, boride phases would form at the interface. In this paper, their morphology, structure and growing mechanism were studied using transmission electron microscopy (TEM). One kind of the borides had chemical formular of Mo2NiB2. Some orientation relations existed between the borides and the surrounding substrate. The borides grew in step mechanism controlled by long-range diffusion of atoms.

Microstructure of braze metal of stainless steel brazed with BAg25CuZn alloy

PAN Hui, SUN Ji-sheng, LIU Xiao-fang

2000, 20(3): 94-97.

[Abstract](1123) [PDF 657KB](352)

Abstract:
The composition and the formation of braze metal microstructure of stainless steel brazed using BAg25CuZn alloy with oxy-acetylene and in a furnace were studied. The microstructures of brazing seams with two brazing methods as brazed and as annealed were analyzed. It is concluded that the microstructure of braze metal consists of rich copper phase, rich silver phase and pseudoeutectic, the cooling speed has a big effect on the microstructure of braze metal, and annealing treatment is beneficial to the homogeneity of microstructure.

Finite element analysis of temperature fields in electron beam welding of alloy GH909

GUO Shao-qing, LI Xiao-hong, MAO Wei, YAN Ming-gao

2000, 20(3): 98-101.

[Abstract](1132) [PDF 168KB](355)

Abstract:
The transienTheat transfer in electron beam welding of GH909 was numerically simulated by using the MARC Finite Element Analysis Software. According to the special heating mode in electron beam welding, which is quite different from arc welding, a model with energy transportation through cavity internal wall was presented. Compared with the mode of energy input obeying Gauss distribution on work piece surface, the new model takes into account the influences of cavity formation on energy absorption, so the simulation results demonstrate the geometry features of electron beam welding more pertinently.

Mechanical properties prediction for P/M superalloy disk by computer simulation

HE Feng, WANG Wu-xiang, YANG Wan-hong, ZOU Jin-wen, WANG Xu-qing, HAN Ya-fang

2000, 20(3): 102-107.

[Abstract](1160) [PDF 943KB](188)

Abstract:
By analyzed the relationship between the mechanical properties of superalloy disks and the cooling rate of quenching, this paper established the basic technology of computer simulation of the quenching process for FGH95 powder superalloy disks, which can predict the microstructure and properties for the alloy. The technology makes it possible to precisely control the quality of quenched FGH9 parts and to increase their service reliability.

Computer simulation of quenching process of P/M superalloy FGH95 turbine disk

WANG Xu-qing, YANG Wan-hong

2000, 20(3): 108-112.

[Abstract](1113) [PDF 744KB](193)

Abstract:
Mechanical property prediction and quench cracking analysis of PREP as-HIP FGH95 and HIP+forging FGH95 turbine disk are studied in this article.Comparative studies show that analytical results very well represent practical ones.The quench cracking studies show that the increase of the radius at the edge of the disk reduce stress.

Study on determination of Sn, Zr, Nb, Ta, Nd, Fe in Ti/TiC composite material by ICP-AES

XIE Shao-jin, DONG Tian-xiang

2000, 20(3): 113-119.

[Abstract](1170) [PDF 240KB](227)

Abstract:
It is described that the study on the determination of Sn,Zr,Nb,Ta,Nd,Fe in Ti/TiC composite material by ICP-AES. The effects on the analytes of matrix and co-exist elements in Ti/TiC composite material and the linear equations of the analytes are emphatically studied. The experiments of acids on the elements especially Ta,Nb,Zr are carried out. The results are obtained with good precision and accuracy.

Study on electrochemical measurement of atmospheric corrosion

SUN Zhi-hua, LIU Ming-hui, LI Jia-zhu, ZHANG Xiao-yun, LU Feng, WANG Jia

2000, 20(3): 120-123.

[Abstract](1072) [PDF 464KB](415)

Abstract:
The Kelvin measurement device of atmospheric corrosion made by ourselves is introduced,including the measurement theory, function and usage, the soft and hard structure, and the initial measurement results. In the device,the vibrating capacitor method is used. The corrosion potential and the polarization curves of metals covered by thin electrolyte layers can be measured without touching the surface under investigation and the electrolyte,using a Kelvin probe as a reference electrode, the advanced method to study the corrosive behavior of the materials at atmosphere is given.

Study on thermogravimetric characteristics for carbon fiber reinforced resin matrix composites

CHEN Xin-wen, LI Xiao-jun, XU Feng-he

2000, 20(3): 124-128,133.

[Abstract](1212) [PDF 221KB](240)

Abstract:
Thermogravimetric characteristics were researched in lab for two styles of carbon fiber reinforced resin matrix composites(CFRRMC) under thermal aging. Curves of thermogravimetric(TG) and thermogravi metric speed(-dTG/dt) vs time at several temperatures were obtained respectively. Subsequently, effects of temperature and time on thermogravimetric characteristics were analyzed qualitatively. Consequently the threshold temperature was determined, at which thermal aging under control of physical aging transformed into another one under control of chemical aging.

Effects of edge joint design on load-carrying capability of canopy transparent material

ZHANG Hong-feng

2000, 20(3): 129-133.

[Abstract](1108) [PDF 183KB](192)

Abstract:
Effects of different edge joint design on load-carrying capability of canopy transparent materials have been studied in this paper.Tensile strength at break and impact energy of edge joint samples were tested.The results show that the material type,edge joint form,and the distance from pore to edge influence the load-carrying capability of the edge attachment.

Effect of solid content of Al₂O₃ slurry on properties of suspension and ceramics

XU Rong-jiu, CHEN Da-ming, ZHOU Yang, LI Bin-tai

2000, 20(3): 134-138.

[Abstract](1244) [PDF 570KB](337)

Abstract:
The effects of solid content on the viscosity and fluidity of Al2O3 slurries used for gel-casting were studied, and the microstructure and properties of Al2O3 ceramics made from those slurries with different solid content were analyzed. Results showed that in order to obtain slurry with high performance, the solid content of the slurry must be controlled. And as the concentration of slurry affects the efficiency of milling and the density of green body, it will also have great effect on the final sintered Al2O3 ceramics. In the case of this paper, 50% of solid content was preferred.

Calcining process of hexaferrite absorber powder

LI Bin-tai, DU Lin-hu, ZHOU Yang, HUA Wen-jun, CHEN Da-ming

2000, 20(3): 139-143.

[Abstract](1083) [PDF 892KB](240)

Abstract:
The influence of calcining process in the synthesis of (Zn1-xCox)2-W hexaferrite absorber powder by the gel-solid-state method on the properties, microstructure and phase characteristics was investigated.The maxim phase content of (Zn1-xCox)2-W was obtained at 1300℃when the calcining temperature varied from 1100℃ to 1350℃.The grain size increased to a desirable size of 20～30μm when precursor was calcined at 1300℃ for 60min.It is concluded that both high W phase content and a appropriate grain size contribute to a high complex permeability of hexaferrite powder in X band.

Synthesis of magnesium aluminate spinel powder by gel solid reaction

TONG Jian-feng, ZHOU Yang, DU lin-hu, CHEN Da-ming

2000, 20(3): 144-147.

[Abstract](1109) [PDF 595KB](344)

Abstract:
A fine pure magnesium aluminate spinel powder was synthesised by gel solid reaction,using Al2O3 and Mg(OH)2·4MgCO3·6H2O as raw materials under given condition.The phase changed according to heating temperatures from 1000℃ to 1250℃.The single phase of magnesium aluminate spinel was obtained by calcining the precursor at temperatures higher than 1250℃. The phase changing process and relationship among calcination parameters, phase composition and image of particle are studied to determine the optimal conditions for the synthesis of fine magnesium aluminate spinel powder. The powder obtained was characterized by XRD,SEM etc. The results of analysis showed that the ultrafine powder is of spinel phase, high purity, good dispersion.This process for preparing fine magnesium aluminate spinel powder was very simple and inexpensive.

Development of higher-performance aeronautical gear steel

ZHAO Zhen-ye

2000, 20(3): 148-157.

[Abstract](2789) [PDF 1152KB](975)

Abstract:
The current status of development of high performance aeronautical gear steel has been evaluated.Three generation gear steels,including high hardness steel used at conventional temperature,high hardness steel used at medium temperature and the steel which possesses ultra high hardness in case,ultrahigh strength with excellent toughness in core,corrosion resistance used at high temperature have been developed.It is the best way to obtain high power density and long life gear to develop higher-performance gear steel, superpure melted and advanced relative technique,such as design,manufacture,heat treatment of gear.

Resent development of fractographic restrostimation on determining fatigue stress

TAO Chun-hu, XI Nian-sheng, ZHANG Wei-fang, XIE Ming-li

2000, 20(3): 158-163.

[Abstract](1101) [PDF 243KB](401)

Abstract:
Application and disadvantages of determining fatigue stress by means of the threshold crack length (ac) and fast spread area (A) were reviewed. The basic principle, method and engineer application of restrostimating fatigue stress by fatigue striation were introduced. The results show that the error of restrostimated fatigue stress in virtue of fatigue striation can be controlled less than 15%. And the measurement error of fatigue crack propagation rate has little effect on the calculation result.

Trends in high damping aluminum matrix composites

LI Pei-yong, DAI Sheng-long

2000, 20(3): 164-171.

[Abstract](1238) [PDF 298KB](360)

Abstract:
The damping characteristics of conventional damping alloys and the recent developments in high damping aluminum (Al) matrix composites were reviewed. Based on the damping mechanisms of these compo sites, some design principles for high damping Al matrix composites are proposed. Especially, the prospects in high damping composites including (Al alloy)/Gr and (Al alloy)/(Zn-Al alloy) are outlined.

Development of honeycomb cell structure and materials

WANG Yu-ying, WU Rong-huang

2000, 20(3): 172-177.

[Abstract](4496) [PDF 662KB](1058)

Abstract:
A new type Korex honeycomb cell materials was introduced. Korex is an aramid/phenolic high mo dulus,high strength true composite honeycomb core. It was first introduced in 1992 in response to industry desires for a lightweight composite core with greater stiffness, strength and fatigue resistance. The mechanical properties and typical application properties for Korex honeycomb core of different cell-density have been also compared in the article. A few new type honeycomb structure have been given. The research for new type honeycomb cell structure and materials will efficiently increase the mechanical properties of honeycomb structure, decrease their structure weight and enhance their working reliability. All these are very beneficial to enlarge the application of honeycomb structure in aerospace and other industry fields.

Review of thermoplastic composites from commingled yarns

ZHANG Bao-yan, BYUN Joon-hyung, KIM Byun-sun, WU Xue-ren, CHEN Xiang-bao, YI Xiao-su

2000, 20(3): 178-186.

[Abstract](1376) [PDF 1354KB](613)

Abstract:
Various thermoplastic fiber/reinforcing fiber hybrid yarns have been introduced in this paper,and commingled yarn method was addressed as one promising technique for preparing thermoplastic composites.The commingling of thermoplastic fiber/reinforcing fiber,textile process of commingled yarns, manufacturing and consolidation of thermoplastic composites from commingled yarns and the properties of composites from commingled yarns were summarized, the application of commingled composites and the main problems in this field were also outlined.The opinions of the authors were also shown.

Development of resistance gradual variation radar-absorbing composites

XING Li-ying, LIU Jun-neng

2000, 20(3): 187-191.

[Abstract](1203) [PDF 513KB](504)

Abstract:
The development of structural absorbing materials is based on the development of advanced compo sites and compose the abilities of radar-absorbing and standing loading. It can make new kind of structural absorbing materials by using new absorbing theory (such as resistance gradual variation piece,circuit analogue, chiral structure). The resistance gradual variation radar-absorbing composites have good character of radar-absorbing designing and can obtain wide band absorbing property through controlling the type (dielectric or magnetic),thickness, loss coefficient and so on. The different structure form can be chosen for different region. The resistance gradual variation radar-absorbing composites have broad perspective.

2000 Vol. 20, No. 3