ISSN 0412-1961
CN 21-1139/TG
Started in 1956

About the Journal

  Current Issue
    , Volume 20 Issue 3 Previous Issue    Next Issue
    For Selected: View Abstracts
    EFFECT OF QUENCHED-IN VACANCIES ON MARTENSITIC TRANSFORMATION IN Fe-Ni ALLOYS
    XU Zuyao (T. Y. Hsu); YAN Linfa (Shanghai Jiaotong University) (Manuscript received 27 February; 1983)
    Acta Metall Sin, 1984, 20 (3): 143-150. 
    Abstract   PDF (1077KB) ( 538 )
    Experimental results show that in some decarburized Fe-Ni alloys the M_s decreases and the strength increases with an increase in quenching temperature above 900℃ with a fixed parent phase grain size. After short time annealing of the quenched specimen, Ms increases and the strength decreases. A model of interaction of clustered point defect (vacancies)with partial dislocations is presented. It is suggested that the lowering of M_s is due to the pinning of the clustered vacancies to partial dislocations, hindering the nucleation of martensite. Preliminary TEM observation of substructure of austenite has comfired this view. From this experiment the energy of formation of vacancy is found to be 1.2-1.4 eV, in good agreement with the known values in Fe-Ni. The activation energy obtained in the annealing process is 0.18 eV, corresponding to the dissociation energy of bivacancies. The effect of quenching stress is also taken into consideration anti it is concluded that a moderate cooling rate of 2500℃/s seems just suitable for studying the effect of the quenched-in vacancies on M_s.
    References | Related Articles | Metrics
    ON THERMODYNAMIC CALCULATION OF Ms AND ON DRIVING FORCE FOR MARTENSITIC TRANSFORMATION IN Fe-C
    XU Zuyao(T. Y. Hsu); ZHANG Hongbing; LUO Shoufu (Shanghai Jiaotong University) (Manuscript received 7 February; 1983)
    Acta Metall Sin, 1984, 20 (3): 151-161. 
    Abstract   PDF (870KB) ( 621 )
    In order to suit the calculation with computer, △G_(Fe)~(γ-α) from various authors are formulated. Ms from various △G_(Fe)~(γ-α) and different models for evaluation of △G_(Fe)~(γ-α), e. g. refined Fither, KRC, LFG and Hsu's are obtained. Comparison is made among these results. The calculated Ms depends on not only the evaluation model of △G~(γ-α) but also △G_(Fe)~(γ-α). Both LFG treatment with △G_(Fe)~(γ-α) from Mogutnov and Hsu's model with △G_(Fe)~(γ-α) from Kaufman et al. are in good agreement with the experimental M_s. However Hsu's model is much simpler than the general accepted LFG's M_s of Fe-C with x_c=0.01 to 0.05 are detected rather accurately and they are consistent with that given by Kaufman et al. Ms of Fe-C with x_c=0.06 by Greninger seems too high. The calculated driving force depends on not only the evaluation model of △G~(γ-α) but also mainly △G_(Fe)~(γ-α) and M_s adopted. It is more likely that the driving force increases with the increament of carbon content.
    References | Related Articles | Metrics
    A STUDY OF P_c PEAK AND ITS BACKGROUND IN PURE A1
    GREMAUD G.; BENOIT W.;(Swiss Federal Institute of Technology; Lausanne; Switzerland); HE Lüping (General Research Institute of Non-Ferrous Metals; Ministry of Metallurgical Industry; Beijing) (Manuscript received 10 August; 1983)
    Acta Metall Sin, 1984, 20 (3): 162-168. 
    Abstract   PDF (580KB) ( 435 )
    Based on a detailed Study of the internal friction peak P_c and its background in pure Al by means of torsion pendulum and harmonic bias stress experiments, a new interpretation of the interaction mechanisms between dislocations and immobile point defects and mobile defects is presented.
    References | Related Articles | Metrics
    CYCLIC DEFORMATION OF ALUMINUM POLYCRYSTALS
    CHEN Xianfeng; LIN Donglian (T. L. Lin)(Shanghai Jaiotong University) (Manuscript received 11 March; 1983; revised manuscript 14 October; 1983)
    Acta Metall Sin, 1984, 20 (3): 169-284. 
    Abstract   PDF (3381KB) ( 509 )
    The cyclic deformation behaviour of Al polycrystals has been investigated at constant plastic strain amplitudes, γ_(pl), over a range 2×10~(-5)<ε_(pl)<4.7×10~(-3). The cyclic hardening curves and the cyclic stress-strain curves were measured and correlated with the change of dislocation substructure in grains and grain boundaries. In this study, an effort.was taken to explore: @1. the change of dislocation substructure as a function of the number of cycles; @2. the effect of the strain amplitude on the dislocation substructure in saturation; and @3. the role of grain boundary in the cyclic deformation.
    References | Related Articles | Metrics
    SUPERELASTICITY OF Ni-Ti ALLOY AND IN SITU OBSERVATION OF ITS PHASE TRANSITION BY SEM
    JIN Jialing (Shanghai Institute of Iron and Steel Research) (Manuscript received 3 January; 1983; revised manuscript 30 July; 1983)
    Acta Metall Sin, 1984, 20 (3): 176-181. 
    Abstract   PDF (1500KB) ( 461 )
    An in situ observation by SEM was made of the phase transition induced by stain in the specially heat treated 51.6 at.-%Ni-Ti ahoy of which the superelasticity might be reached to such extent of its maximum elastic strain up to 17%. The phase transition is shown as two stages, namely, pre-martensitic and martensitic. The alloy reveals a behaviour for superelasticity, i. e., if the strain exceeds no more than its elastic limit, the whole transition process may be reversible, and the macro-or micro-feature may be back to beginning after unloading at any point of the curve. However, the intergranular cracks and the internal slips may be appeared, as well as the unreversible residual strain may be then remained if it exceeded the limit.
    References | Related Articles | Metrics
    REDISTRIBUTION OF HYDROGEN IN Ti ALLOY Ti-5A1-4V STRESSED INHOMOGENEOUSLY AND ITS EFFECT ON FRACTURE PROPERTIES
    HUANG Xianya; ZHU Zufang (General Research Institute of Non-Ferrous Metals; Ministry of Metallurgical Industry; Beijing); XIAO Jimei (Hsiao Chi-mei) (Belling University of Iron and Steel Technology) (Manuscript received 18 April; 1983)
    Acta Metall Sin, 1984, 20 (3): 182-288. 
    Abstract   PDF (3795KB) ( 638 )
    Hydrogen was introduced into the region 13 mm beyond the crack tip of a modified WOL specimen of Ti alloy Ti-SAl-4V. The delay cracking was growing up in the specimen about 20 months later. The results of an ion probe microanalysis showed that the hydrogen concentration coefficient at the maximum of triaxial stress in the front of crack tip is much greater than the theoretical value exp((?)_Hσ_h/RT) predicted by thermodynamics. Observations by metallography and TEM proved that the titanium hydrides of fct and fcc lattice precipitate at α/β interphase boundaries and interfaces between a facets, The delay cracking takes place just along these interfaces. An analysis by fracture mechanics indicates that K_(IH)≤0.46K_(IC). Based upon the above mentioned experimental results, discussions were made on the extent of the hydrogen redistribution in Ti alloy under a stress gradient, on the kinetic feature of this process, as well as on the possible causes of falsity in similar experiments.
    References | Related Articles | Metrics
    COMPARISON OF STRESS CORROSION CRACKING BETWEEN CAST AND FORGED STEELS IN WATER
    CHU Wuyang; XIAO Jimei (Hsiao Chi-mei); LI Wenxue; ZHANG Yanguo (Beijing University of Iron and Steel Technology) (Manuscript received 1 April; 1983)
    Acta Metall Sin, 1984, 20 (3): 189-196. 
    Abstract   PDF (902KB) ( 614 )
    The stress corrosion behaviour in water of the cast steel in contrast with the forged steel of same heat has been examined comparatively. It was shown that the activation energy of crack growth under stress corrosion of both cast and forged steels is identical, i.e. Q= 5540 cal/mol, and is in agreement with the apparent diffusion activation energy of H_2 permeation in steel. The da/dt for cast or forged steel increases no matter whether cathodic or anodic polarization, but the former influences predominantly. Correspondingly, the steady-state H_2 permeation flux increases steeply with the increase of polarizing current either cathodic or anodic polarization. The influences of polarization upon da/dt and H_2 permeation flux are similar, The testing temperature is found in a less effect on K_(ISCC). The K_(ISCC) of the cast steel determined is larger than that of the forged steel. It may be due to that the steady-state permeation flux for the forged steel is twice as many as that of the cast steel. For both cast and forged steels, the fracture modes are clearly dependent upon K_1 at the crack tip and a transition from dimple to quasi-cleavage or intergranular is observed on the fracture surfaces with decreasing K_1.
    References | Related Articles | Metrics
    KINETICS OF CEMENTATION OF Ag WITH Cu IN AMMONIACAL SOLUTION
    KE Jiajun; YUE Liangdong (Institute of Chemical Metallurgy; Academia Sinica; Beijing) (Manuscript received 13 June; 1983)
    Acta Metall Sin, 1984, 20 (3): 197-203. 
    Abstract   PDF (730KB) ( 488 )
    A thermodynamic analysis of cementation of Ag with Cu in ammoniacal solution has been carried out. The calculated results indicated that this cementation reaction is possible thermodynamically. The rotating disc of Cu has been used to study the kinetics of Ag cementation on metallic Cu in ammoniacal solution. Two stages of reaction rate were found in this cementation process, i.e., an initial slow rate and a second enhanced rate. The deposit morphology influences the cementation rate significantly. The initial stage of reaction corresponds to deposition on a relatively smooth surface and the reaction kinetics is controlled by mass transfer. The increased rate of the second stage reaction is due to the development of a structured surface deposit which effectively increases the surface area available for the cementation reaction.
    References | Related Articles | Metrics
    A STUDY OF THE EQUILIBRIA BETWEEN RARE EARTH ELEMENTS AND SULPHUR IN MOLTEN IRON
    HAN Qiyong; DONG Yuanchi; FENG Xi'an; XIANG Changxiang; YANG Sifu (Beijing University of Iron and Steel Technology) (Manuscript received 4 December; 1982; revised manuscript 4 October; 1983)
    Acta Metall Sin, 1984, 20 (3): 204-213. 
    Abstract   PDF (689KB) ( 684 )
    By means of radioactive isotope, the measurement of the content of rare earth elements in electrolytes, excluding that in the form of inclusion, was made to determine the equilibrium constants of Ce-S, La-S and Nd-S, and the relating interaction coefficients. At1600℃, K_(ceS)=2.70×10~(-6) e_s~(Ce)=-2.36 K_(LaS)=7.41×10~(-7) e_S~(La)=-1.51 K_(NdS)=2.57×10~(-6) e_S~(Nd)=-1.54 The dependence of the concentration products Ce-S on [%C] in the system Fe-Ce-S-C was evaluated.. The interaction coefficient e_(Co)~C was determined to be—0.43. The reason why the higher values of the RE-S equilibrium constants were obtained by previous workers has also been discussed.
    References | Related Articles | Metrics
    A NOTE ON BEHAVIOUR OF NON-LINEAR DEPENDENCE OF LOW FREQUENCY LOSS UPON FREQUENCY FOR AMORPHOUS ALLOYS
    ZHANG Yanzong (Shanghai Iron and Steer Research Institute) (Manuscript received 24 February; 1983; revised manuscript 5 July; 1983)
    Acta Metall Sin, 1984, 20 (3): 214-220. 
    Abstract   PDF (526KB) ( 493 )
    The behaviour of non-linear dependence of low frequency loss upon frequency has been approached on the basis of the analysis of low frequency loss curves for two types of amorphous alloy. The loss curves were analyzed and calculated by introducing two non-linear losses: the thermal fluctuation magnetic after effect and the micro-eddy current loss. The results show that the non-linearity is mainly attributed to a thermal fluctuation magnetic after effect and a numerical variation of the magnetic domain with frequency.
    References | Related Articles | Metrics
    EFFECTS OF IONITRIDING ON STRUCTURE OF NITRIDED LAYER AND SUBSTRATE TO Ti AND Ti-6A1-4V ALLOY
    ZHANG Lixin; LI Liguang (Institute of Metal Research; Academia Stnica; Shenyang); PENG Hongzhen; WANG Jiuying (Shenyang Institute of Metallurgy)(Manuscript received 2 April; 1983; revised manuscript 17 October; 1983)
    Acta Metall Sin, 1984, 20 (3): 221-291. 
    Abstract   PDF (5197KB) ( 549 )
    The structures of the nitrided layer and the substrate to commercially pure Ti and Ti-6Al-4V alloy after ionitrided at 750—920℃ have been examined by X-ray diffraction, metallography and EPMA. An α'-Ti (Al,N) solid solution phase rich in Al is found between the nitrided layer and the substrate of Ti-6Al-4V alloy as an obstruction of N_2 to diffuse through the substrate, and then the ionitriding behaviour of the alloy will be alterred. It was also observed that the texture of substrate of these two ionitrided metals varied considerably. Their preferred orientation in inverse-pole-figure of normal sheet changes from (0001) to (o110) and (2131), especially concentrated in the centre part of the specimen. This seems to be the particular phenomenon owing to the ionitriding technique.
    References | Related Articles | Metrics
    THE SmCo_5 AND Sm_2Co_(17) TYPES OF STRUCTURES FORMED IN THE LATEXES
    HANESAKA M.; NAKASHIMA H. (Nakasaki University; Japan); WANG Yong (Beijing Metallurgical Research Institute) (Manuscript received 21 October; 1983)
    Acta Metall Sin, 1984, 20 (3): 230-294. 
    Abstract   PDF (2904KB) ( 788 )
    Particles with different diameters in the latexes are observed under a metallurgical microscope. The large, middle and small particles form the crystal structures of the SmCo_5, Sm_2Co_(17) types and the Laves phase of intermetallic compounds through nucleation and growth. An amorphous structure, the crystal structure at composition off the 1:5 or 2:17 stoichiometry, point defects and boundaries between various types of structures are observed in the latexes. Latexes are shown to be useful to study at atomic level the morphology of Sm-Co and Sm-Co-Zr alloys.
    References | Related Articles | Metrics
    ACOUSTIC EMISSION FROM SOLIDIFICATION OF Sn-Bi BINARY ALLOY
    JI Shichen; ZHU Zuming; WANG Guozhi; LI Ying'ao; HU Zhuangqi (Institute of Metal Research; Academia Sinica; Shenyang)(Manuscript received 28 February; 1983)
    Acta Metall Sin, 1984, 20 (3): 237-242. 
    Abstract   PDF (422KB) ( 425 )
    The solidification of the Sn-Bi binary alloy has been monitored by sensitive acoustic emission equipment. It is found that the characteristic acoustic emission is dependent on the material nature, the alloy composition and the solidification process. The acoustic emission technique is applicable to determine the phase diagram of the Sn-Bi binary system and to monitor the solidification processing. Thus, it seems that this technique may be available means to theoretically and technologically study the dynamical micro-mechanism of the solidification of metal and alloy as well as of the casting process.
    References | Related Articles | Metrics
    EFFECT OF SLAG COMPOSITION ON Mg, Al OR Ti CONTENT IN Ni-BASE SUPERALLOY DURING ESR
    CHEN Chongxi; GAO Rongfu; ZHAO Wenxiang (Beijing University of Iron and Steel Technology) (Manuscript received 14 January; 1983)
    Acta Metall Sin, 1984, 20 (3): 243-251. 
    Abstract   PDF (708KB) ( 606 )
    The effect of the composition of slag system CaF_2-MgO-Al_2O_3-CaO-0.5 mol % TiO_2 on the contents of Mg, Al and Ti in Ni-base superalloy during ESR has been investigated. In the mole concentration range of the slag: 0.10≤N_(MgO)≤0.25, 0.05≤N_(Al_2O_3)≤0.21 and 0.05≤N_(CaO)≤0.15, and at temperature of the slag pool about 1690±10℃, the wt-% elementary content in the superalloy after ESR may satisfy the following functions: [Mg]=0.881[Al]_0~(0.641)N_(MgO)~(4.114-2.835N_(CaO)+1.077lnN_(Al_2O_3))N_(Al_2O_3)~(1.282) [Al]=[Al]_0-(0.19+0.804N_(CaO)~(0.454)-1.70N_(Al_2O_3))vA/45.36V v=0.148+0.479N_(Al_2O_3)+0.348N_(MgO)-0.378N_(CaO) where [Al]_0 is the Al content in the electrode; A is the area in cm~2 of the metal pool/slag interface and v or V is the mett rate in kg/min of this study or others respectively. [Ti] increases slightly with the increase of N_(CaO) and without relevance to the variation of N_(MgO) or N_(Al_2O_3).
    References | Related Articles | Metrics
    CONTROL OF SOLIDIFICATION PROCESS DURING CONTINUOUS CASTING OF STEEL
    CAI Kaike (Beijing University of Iron and Steel Technology) LIU Fengrong (Hebei Institute of Mining and Metallurgy) (Manuscript received 18 September; 1982; revised manuscript 14 March; 1983)
    Acta Metall Sin, 1984, 20 (3): 252-260. 
    Abstract   PDF (613KB) ( 647 )
    An investigation has been carried out into the "metallurgical criterion" of the slab solidification during continuous casting. The effect of following variables on the metallurgical criterion has been studied by the mathematical model of heat transfer: casting speed, spray water intensity, water distribution in spray zone, superheat in tundish, convection in liquid pool and temperature of spray water. Considering these factors, a nomogram of the productivity related to slab thickness, casting speed, spray water intensity and depth of liquid pool was prepared so as to selecte reasonably the technological parameters and to control scientifically the operation.
    References | Related Articles | Metrics
    AN EMPIRICAL CONCEPT ON FORMATION OF BINARY AMORPHOUS ALLOYS BY LIQUID QUENCHING
    LIU Zhiyi (Institute of Physics; Academia Sinica; Belling) (Manuscript received 26 April; 1983)
    Acta Metall Sin, 1984, 20 (3): 261-269. 
    Abstract   PDF (722KB) ( 521 )
    A proposal was made of the increasing tendency of amorphous formation of the binary transition metal alloys caused by the incongruent-and congruent-melting compounds of lower melting temperature on the basis of synthesis of the previous experimental data, including the author's. The effects of crystalline structure, atomic radius difference, electronic structure and electro-negativity difference of eIements were discussed. An empirical approach to the formation of binary amorphous alloys by liquid quenching was summarized. Thus, certain new alloy systems, e.g., Ti-Pd, La-Si, Zr-Ga, Hf-Pd, etc. may be developed.
    References | Related Articles | Metrics
    TEMPERATURE (4.2—300K) DEPENDENCE OF ELECTRICAL RESISTIVITY OF FeMB (M=Mn, Mo) AMORPHOUS ALLOYS
    SHEN Baogen; ZHAN Wenshan; ZHANG Zhiying; WU Zonglin (Institute of Physics; Academia Sinica; Beijing) (Manuscript received 27 June; 1983)
    Acta Metall Sin, 1984, 20 (3): 270-276. 
    Abstract   PDF (537KB) ( 484 )
    The electrical resistivity of (Fe_(1-x)Mn_x)_(80)B_(20) (x=0—0.25) and (Fe_(1-x)Mo_x)_(80)B_(20) (x=0.05—0.18) as a function of temperature between 4.2—300K has been studied. In all samples, the minima of the resistivity vs temperature are found. Below temperature T_(min) at which the resistivity is minmum, their resistivity can be described by a logarithmic temperature dependence and may originate from the Kondolike scattering. Over T_(min), it has a T~2 temperature dependences and may originate from both electron-phonon and localized spin-fluctuation scattering.
    References | Related Articles | Metrics
    INTERACTION BETWEEN A1-Si FILLER METAL AND BASE METAL FOR ALUMINUM BRAZING
    CHEN Gengbao; WU Jinhua; LI Geyang (Shanghai Jiaotong University) (Manuscript received 30 July; 1983)
    Acta Metall Sin, 1984, 20 (3): 277-279. 
    Abstract   PDF (2084KB) ( 569 )
    The interaction between Al-Si eutectic filler metal and base metal in keeping the fillet at brazing temperature has been studied. It was shown that the interaction is mainly the solution of base metal into filler metal, and the diffusion of filler metal through the grain boundary of base metal has not been observed yet.
    References | Related Articles | Metrics
    A PROBLEM ON METALLURGICAL PROCESS DURING ALUMINUM BRAZING——Wish to Discuss with Mr. CHEN Genbao and Others
    ZHANG Qiyun; LIU Shuqi (Dept. of Chemistry; Beijing University) (Manuscript received 5 September; 1983)
    Acta Metall Sin, 1984, 20 (3): 280-282. 
    Abstract   PDF (187KB) ( 480 )
    The metallurgical process of the fillets formed during aluminum brazing has been discussed. The dissolve of base-metal into the liquid fillet metal was first beginning at its crystal boundaries, owing to the homogenization of the liquid phase, Si permeates into the boundaries. Meanwhile, Si in the liquid diffused into Al granules, thus the a-phase formed.
    References | Related Articles | Metrics