Guo Xiping, Fu HengZhi. High Temperature Stress Rupture of a Single Crystal Superalloy NASA IR100[J]. Journal of Materials Engineering, 1995, 0(6): 3-6.
The microstructure and high temporature stress rupture properties of NASA IR 100 single crystalswere investigated under beth as-cast and heat treated conditions. It was found that creep voids initiated atγ/γ'eutectic,W-riched phase, porosity and γ-γ'interfaces,then grown into dimples and finally unitedwith each other by tearing edges.
Zhang Jinghua, Zhang Zhiya, Li Yingao, Guan Hengrong, Hu Zhuangqi. Misfit and Antiphase Boundary Strengthenings of a Single Crystal Nickel Base Suporalloy[J]. Journal of Materials Engineering, 1995, 0(6): 7-9.
The antiphase boundaries(APS)formed in the ordered γ'phases is a dominant strengthen mode.There are three typos of mechanisms for formation of the antiphase beundary to be found in the alloy:One is the nismatch arrangement for the order atoms in a leeal area,the second is dislorations with 1/2<110> cut into the γ'phases,the last one is induction by the disloration network in the matrix. Thecontribution of the aniphase boundary energy to the strength of the alloy is given by:τ=KS3/b2a3(Tc3frs/G)1/2 where τ is the resistance force to deformation provided by the APB energy, S the long-range ordered de-grees,Tc the transition temporature from the ordered to disordered structures in the γ'phase,f the volume fraction of the γ' phase in the alloy,rs the radiu of the γ' particles,G the shear medulus,K the propotional constant.
Wei Pengyi, Li Jianguo, Fu Hengzhi, Gui Zhonglou. Directional Solidification Processing for Super-refinement of Submicrostructure of Single Crystal Superalloy DD3[J]. Journal of Materials Engineering, 1995, 0(6): 10-11,42.
MicrostrucnJral evolution characteristics and its response funtions to processing parameters of Sin crystal(SC)suporalloy DD3 was investigated with the ZMIAlC senlp with a interface temporan1re gra ent of 700～1200K/cm.Results show:the interface temporature gradient was so high that the drawing velocity range for columnar crystal growth was extended up to a higher value,and make it possible to refine the submicrostructure of SC. The primary spacing of SC submicrosture in SC bars obtained were five～ten times smaller than that of Seed-crystal prepared with traditional HRS DS Process. The mecha-nism of those strucural evolution was also discussed.
Lao Yueling. LAGB in Single Grytal Superalloy[J]. Journal of Materials Engineering, 1995, 0(6): 12-14.
In this paper, the low angular grain toundary(LAGB)formed in cast DD3 and ЖC-36SC products and it's effect on propedes was investigated.The results showed that there are more LAGB in the structure of DD3 se preducts cast by DS furnace and it's creep rupnire properties were reduced by afactor of 70~80%.
Liu Zhongyuan, Li Jianguo, Shi Zhengxing, Fu HengZhi, She Li, Chen Rongzhang, Wang Luobao. The Effect of Solidification Rate on Mechanical Properties and Microstructure of Directionally Solidified Superalloy DZ22[J]. Journal of Materials Engineering, 1995, 0(6): 15-18.
This paper deals with mechanical properties and microstructtire of directionally solidified superalloy DZ22 at two sotolidification rates with zone melting and liquid metal cooling(ZMLMC)directional solidifi-cation process.Exporimental results show that the stress-rupture life of DZ22 at 980℃ and 220MPa was increased from 71 hours and 50 nunutes to 168 hours and 5 minutes at relatively high solidification rate. The primary and secondary denhatic arm spacing λ1 andλ2 of DZ22 was decreased form 105μm and 32.7μm to 68μm and 16μm respoctively.The nucrosegregation of elements was decreased.The mor-phology,Size and distribution of γ',eutectic(γ-γ')and MC was changed obviously.
She Li, Mu Shouchang, Yin Keqin, Wang Luobao. Study of the Directionally Solidified Superalloy DZ22B for Turbine Blades[J]. Journal of Materials Engineering, 1995, 0(6): 19-21.
Z22B is an improved directionally solidified suporalloy for turbine blades.The composition is characterized by only 1.0% Hf.It's mechanical properties are comparable to American famous directionally solidified superalloy PWA1422.No TCP phase are found to precipitate after high temporature exposure for 5000 hours. The mechanical properties remain steady. This alloy has been served as high pressure blade material in a aeroengine and become commercialized.
Wang Zhaohu. Influence fo Prolonged Ageing on Microstructure and Mechnical Proporties of suporalloy DZ125[J]. Journal of Materials Engineering, 1995, 0(6): 22-24,18.
The long-term aguing of directionally solidified superalloy DZ125 at 900℃ for 3000 hours was examined.The results show that there is a stable microstructure and no TCP phase in agreement with the result of phse calculation. However,after ageing for 3000 hours,the stress-rupture life is slightly decreased,this may be related to the coarsening of γ'phase.
Liu Faxin, Yuan Wenming, Tang Xin. Study on the Displaying and Rating of the Grain Size of the Fine Grain Casting of K418 Alloy[J]. Journal of Materials Engineering, 1995, 0(6): 25-27.
The displaying and rating of grain size of the fine grain casting of K418 alloy have been diseussed,which are feasible through the practical using.
Wang Wen. Research of High Precision and Thin Size Superalloy Remelting Stock Made with Metallic Mold[J]. Journal of Materials Engineering, 1995, 0(6): 28-30.
This paper introduces briefly the technological requirement for thin K18C remelting stock,and discuases that,when preduced with metal model,it would posesse precision size,smooth appearance and purest quality etc. A great amount of the material have been used in the production of sporeparts of superalloy.
Zhang Zhiwei, Jin Jinxiu, Zhang Yuchun, Qi Ying. The Microstructure and Property of Directed Aged GH169 Alloy[J]. Journal of Materials Engineering, 1995, 0(6): 31-34.
The influence of heating temperature and deformation rate on the grainsize, amount of δ-phase separation and propornes of DAGH1 6 9 alloy compreaser disk,forged by hydraulic press,was investigated.
Wu Zhongtang, Dai Xiuyang, Gui Zhonglou, Tang Dingzhong, Zhong Zhenggand, Chen Dehou. Vacuum Induction Melting of Single Crystal Superalloy DD3[J]. Journal of Materials Engineering, 1995, 0(6): 35-37.
MC crabides, oxide inclusions and microporosities in single crystal superalloys are the crack sourcesand crack propagation paths of creep and fatigue. In order to reduce detrimental influence of MC carbides,oxide inclusions and microporocities,it is defined that [C]≤0.010wt%(it will be better,when[C]≤0.006wt%),[O]≤0.001wt%,[N]≤0.0012wt%in the single crystal superalloy DD3.Allthe decarbenization,deoXidation,denitrogenation and desulphurization are camed out through CO rcactionwith ebullition.The propor vacuum induction melting process has been obtained for preducing the single crystal suporalloy DD3 in which[C]≈60ppm,[S]≈10ppm,[N]≈3ppm and[O]≈5ppm by strictly controlling the content of the carben and improving the technique.
Ruan Zhongci. The Selection of Measurement Parameters in Quantitutive Metallography by Image Analyzer[J]. Journal of Materials Engineering, 1995, 0(6): 38-39,6.
In this paper,propor selection of the measurement parameters(magnification,number of fields measured)in quantitative metullography by image analyzer and its importance to measurement results are reviewed,Through the example discussed,the selection principle of the measurement porameters is suggested.
Lang Yefang. Domestic Single Crystal Furmace with a High Temperature Gradient[J]. Journal of Materials Engineering, 1995, 0(6): 40-42.
Design highlight and main structure of domestic single crystal fumace with high temperature gradientis intrtoduced and compared with several commercial sigle crystal furnaces abroad.
Wu Peiyuan. The Failure Analysis of Fatigue Damage in a Flight Accident[J]. Journal of Materials Engineering, 1995, 0(6): 43-48.
In this paper,the distinguishing fatigue damage failure in a flight accident is summarily discussed.Including the basic feature of fatigue damage failure that emergrs a flight accident,the basic feature of parts of failure damage fracture that are emerged by the flight accident,the summery analyses of the relationship of material,damage defect and active stress in case of complex fatique dsmage fracture.
