航空材料学报

The Influence of Crystallographic Orientation on the Crack Propagating Rate of LCF of DD3 Single Crystal Nickel Base Superalloy

Zhang Huibing, Zhang Guohuan

1987, 7(2): 1-7.

[Abstract](1343) [PDF 4310KB](98)

Abstract:
In this paper the crack propagation of LCF of DD3 single crystal nickel base superalloy for different orientations at 760℃ was studied. It was found from the results that the crystallograph ic orientation has influence to the crack propagating morphology and rate. With the difference of cry stallograph ic orientations of compact tension specimens,either level propagating in which the propagating direction is perpendicular to the stress axis or incl ined propagating in which the propagating direction is inclined to that direction will appear.In incl ined propagaing case.the propagating rate of 〔001]orientation is the highest. In level propagating case, that of〔111]is the lowest. The fra-ctographies and propagating features were analys ised and it was considered that the two kind propagatings are all the continuing of stage I propagating all are the process of slip controlling.

The Effect of Stress—ageing on Structure and Properties of GH150 Alloy

Huang Fuxiang, Dong Yunguo, Zhao Yuxin

1987, 7(2): 8-14.

[Abstract](1264) [PDF 4940KB](66)

Abstract:
In tms paper,the structure and properties of GH150 alloy after stress-ageing at 600℃392MPa、700℃196MP and 800℃78MPa for 200 and 500 hours has been researched .It is indicated that the alloy is further strengthened after long stress-ageing at 700℃,but stress-ageing at 800℃ significantly decreases the room-temperature plasticity and h igh temperature rupture strength of the alloy. It is known by regress ion analysis that the alloy can be used at the conditions of 600℃392MPa and 700℃196MPa for at least 5000h and 700h respectively。

The Static Recrystallization of TC11 Alloy after High Temperature Pre-defora ation

Yang Quanmin, Zhang Baochang, He Min

1987, 7(2): 15-21.

[Abstract](1241) [PDF 4437KB](61)

Abstract:
After high temperature pre-deformation at various cleforraation parameters, the effects of heat treatment temperature and remaining time on the static recrystallization of grains at low magnification were investigated. It was shown that, for TCll alloy, the static recrystallization temperature is under but very near the +/ transition temperature.When the specimens are remained at (t10℃) for 10 hours, the static recrystall ization does not occur, and at (t5℃) for 30 minutes, the fraction of static recrystallization of grains amounts to 70% and the recrystallized grains are fine (70m), and at t for 1.5一5 minutes the static recrystallizat ion is completed,but the grains are coarse (200m)

The Behaviors of Fretting of Titaniu n AlloysTCll and Ti-1023

Wang Shihong, Liang Yourring, He Xiao, Li Dongxing, Dong Xianglin

1987, 7(2): 22-28.

[Abstract](1228) [PDF 4364KB](59)

Abstract:
The experimental studies of fretting on TC11 and Ti-1023 alloys have been made in air. The relation of weight loss to mechanical variables i.e. normal load, amplitude of si ip and frequency of vibration were determinded. The experimental results shown that the fretting behaviors for two kind of titanium alloys were similar. The fretting mechanism for TC11 and Ti-1023 mainly belonged to delamination rather than adhesion. The abrasive wear caused by debris produced from rubbing together of contact surface have small effect on fretting. In initial stage, delamination was due to seperating of metal at points of contact from matrix and followed by oxidizing, in stable stage, it is embrittlement oxidizing delamination.

Liang Yourring, He Xiao, Li Dongxing, Dong Xianglin (22) The Multiple Twinning of Fe₄Al₁₃ as a Heterogenous Phase in Commercial Al-Zn-Mg-Cu Alloys

Hua Mingjian, Li Chunzhi, Yan Minggao, Wang Junjie

1987, 7(2): 29-34.

[Abstract](1283) [PDF 3805KB](62)

Abstract:
TEM investigation has been made on the heterogenous phase in two commc-rcial Al-Zn-Mg-Cu alloys. In contrast to previous work involved in similar work, it is found that -Fe4Al13 is the main constituent phase, in which multiple twins and heavy stacking faults are frequently observed. It is revealed by SA-EDP that has two mirror planes, (200)and (201), the interplanar distance of which is nearly identical while the angle between which is 36.2 so that the orientation relationship of neighbouring twins may be equivalently considered to rotate 2/10 about〔010].A SAEDP with tenfold symmetry has been recorded and discussed in relation to quasicrystals.

Research on Polyethersulfone Resin and Its Composites

Liu Huiuao, Shi Dingdu, Shen Sitang

1987, 7(2): 35-41.

[Abstract](1252) [PDF 3607KB](63)

Abstract:
Polyethersulf one re s in has excellent heat resistance, toughness and d lele-ctricity.lt is one of the most interesting resins that are investigated and developed in s itus.This paper reported Imide Ether(IE) used to modify Polyether-sulfone(PES)lOOP and the resulted resin was indicated by improved heat resistance and strength.The modified PESIOOP has been used to blend with PES200P, and it makes the flexcture strength of glass reinforced plastic increase 12%, as well as its thermal performance was not decreased.

Water Effects on Polycarbonate Sheets

Wu Xuanzheng, Lin Dunyi, Shi Weiqi, Fan Tang

1987, 7(2): 42-50.

[Abstract](1245) [PDF 6089KB](79)

Abstract:
In this paper, studies that water efiects on polycarbonate sheets have been done using density, tensile stress-strain curves, impact strength, SEM etc. test technologies. The results of studies indicate that trace water can remarkably efiect process ing,ductile, strength and physical structure. Water can corrosive the surface of PC sheets and it will effect optical property and processing When water absorption is close to 0.31%,the ductile-brittle transition of PC will occur and the phenomenon is observed by tensile fracture strength,fracture strain and SEM. Last, mechanisms that water efiect on PC sheets have been suggested.

An Investigation on MIG Welding of Superalloy,Stainless Steel

Hou Yunian, Hao Junming, Yang Peili

1987, 7(2): 51-55.

[Abstract](1252) [PDF 3005KB](76)

Abstract:
In this paper MIG welding is recommended to be used to weld superalloys (GH44 and GH39) and stainless steel (lCrisNi9Ti), which is of low energy input,high welding speed,and excellent appearance of weld.The welding joints by MIG have better mechanical properties than those by TIG. This paper explains a problem in product ion which has been solved by mean s of MIG.With the result that trim tabs and combusion outer casing of a certain type jet engine arc successfully welded. The quality of these products has reached the level of the foreign prototype engine.

Investigation on Superplasticity of Ti-lOV-2Fe-3Al Alloy

Liu Weimin, Pan Yaqin

1987, 7(2): 56-61.

[Abstract](1193) [PDF 3772KB](63)

Abstract:
The superplastic deformat ion behaviours of American new type near-P alloy Ti-10V-2Fe-3A have been investigated. It showed that the alloy can deform su-perplastically at temperatures 700750℃ and strain rates 8.2510-4～1.210-3s-1. The maximum elongation is 910% with high m. The superplastic deformatoin of this alloy is of the characters of grain boundary siiding mechanism.

The Applied Study on Life Prediction of Cyclic Creep of GH36 Alloy

Lu Younian, He Jinrui

1987, 7(2): 62-68.

[Abstract](1263) [PDF 4050KB](66)

Abstract:
Low cycle fatigue and cyclic creep are the mein life limiting factors of long term engine disk. Experimonts regarding the behaviour of cyclic creep have been preformed for GH36 alloy at 650℃. Expsrimental resullts are presented showing that creep is the main damage source of liie in cyclic creep. In addition, several life prediction methods have been examined according to experiment data. It is found that the models of strain and energy are better than the time-1ife fraction rule.

Weight Function and Dugdale Model Solution for Compact Specien

Zhao Wei, Wu Xueren

1987, 7(2): 69-72.

[Abstract](1274) [PDF 4115KB](82)

Abstract:
The paper presents closed-form we ight function for compact specimen,based on which stress intensity factor express ion for known arbitrary uncracke|d stress distribution is given. Stress intensity factors and crack face displacements for load cases of a pair of concentrated forces act ing at the crack surfaces and a segment of uniform crack face pressure have been considered in detail. Further the Dugdale model plastic zone size and the Dugdale model crack tip opening d is place ment(CTOD) for the pin load case have been determined with the weight function method. The weight-function-based solutions were compared with recent results of Mall and Newman by the boundary collocation technique. Very good agreement was obtained.The accuracy and efficiency of the present analyses for compact specimen demonstrate the usefulness of the closed-form weight in frac-tuer and fatigue crack propagation analyses。

1987 Vol. 7, No. 2