During the past four decades, China's superalloy developed from nothing into an integrated system, from imitation to innovation, and a series of innovative achievements have been obtained. It primarily meets the demands of aviation and aerospace industries and civil uses. In this paper, the course of the development of China's superalloy was reviewed and the characteristics of the superalloy system as well as the innovation in the development were summarized. The experiences obtained and the gap to be bridged were also pointed out.Keywrods:superalloy

A critical review is made on the recent development of the research on non-linear anelastic internal friction. The chief difference between the non-linear anelastic internal friction and its linear counter part is that in the linear case only internal friction peaks versus temperature and versus frequency appear, whereas in the non-linear case appears also internal friction peak versus strain amplitude within the temperature region of the internal friction peak versus temperature,Since the discovery of the non-linear anelastic internal friction in 1950, two systems exhibitiing non-linear anelastic internal frictions have been found and investigated: (1) The interacti0n between point defects (vacancies and solute atoms) and dislocations. A series of experimental results have been obtained concerning this subject, appropriate physical models have been suggested and priliminary theoretical analysis have been attached. (2) The interaction between dislocation and grain boundaries (bamboo grain boundary and bicrystals). Some experimental results have been obtained concerening which further experimental and theoretical studies are requird.

This paper briefly reviews the evaluation of technological policy of ironmaking in China after the founding of People's Republic and forecasts the prospect in the 21st century.

The steel plant process has been modeled as a multi-dimensional mass-flow control system in which the transformation of mass states, mass properties and flow control have been mixed. The system shows viscous characteristics of sets of rigid, flexible elements and their relationship. Its running mode appears as a stable or non-stable resonance of elastic/semi-elastic chain with para-continuous/discrete nature. Influenced by external stimulus, it will produce responses that have different types and sluggishnesses. Based on the above analysis, this paper will propose a theoretical frame of an integrated description of steel plant process. The object of metallurgical industry and the optimization of steel plant structure has also been put forward.

During 1921-1927, E.C.Bain made many important contributions to metallography by means of X-ray powder diffraction studies. He discovered the AuCu3 and Au3Cu superlattices, the face-centered structure of the Fe-Mn austenite, the Fe3W3C (or M6C) carbide in high-speed steels, and the Sigma phase in Cr-Ni stainless steels. Through a comprehensive study of the transformation of austenite, he proposed a crystallographic relationship (the Bain relationship) between austenite and martensite and developed the method to determine the amount of retained austenite by X-ray diffraction. This finally led him to study the isothermal transformation of austenite in 1930 and obtained a new transformation product at intermediate temperatures which was named Bainite after him. No doubt he was one of the pioneers in the development of X-ray metallography.

Kinetically, martensitic transformation may be classified as athermal and isothermal transformations. According to thermodynamics and interface motion characteristics, martensitic transformation may be divided into thermoelastic, semi-thermoelastic and non-thermoelastic transformations. Criterions for thermoelastic transformation can be drawn as: (1) a small critical driving force and a small hysteresis; (2) reversibility of the motion of the interface between martensite and parent phases. (3) the shape strain is accommodated elastically and the stored energy is available to contribute a part of the driving force for the reverse transformation. From different nucleation processes, the martensitic transformation may be classified as: (1) nucleation nearly through the local soft mode in which the parent strengthening hinders the onset of the transformati0n; and (2) nucleation by stacking fault in which the parent strengthening does not affect the M, markedly and there will not appear a considerable lowering of the Young's modulus at the temperature interval of the internal friction peak exhibition as a result of the martensitic transformation fcc→ hcp. Thequasi-martensitic transformation may be termed for a martensitic transformation with week first order.

In this paper, we reviewed that a first principles interatomic potential and the theoretical calculation method of interaction energy between atoms, which are developed by us. Meanwhile, the important role of the energetic functions in the studies of the electronic structure of the impurity-grain boundary complexes and the basic properties of the crystal are reported. On the other hand, the electronic structure and the doping effect of intermetallic compound are studied by the use of first principles method and Green function method. The quantum effect of impurity-grain boundary complexes and the correlation mechanism between the electronic structure with the property of a1loy and dislocation reaction are explored.We find that Boron and Nitrogen have strengthening effect for the cohesion of grain boundary, and the phosphorous and sulphur are embrittle exements in the grain boundary of Ni-base alloy. Molybdemum influence the deformation mechanism of Ti-Al intermetallic compound.

The phase equilibria and thermodynamic parameters, as a function of temperature, of twenty nine ternary and quaternary Fe-base metallic systems containing one of representative elements (Ce, Y, La, Nd, Sm) and S, O, S+O, C, N, Sb, Sn, Pb, P, Cu, Ti, Nb,V respectively, of seven Ni-base metallic systems containg one of the Ce, Y, La elements and S, O, S+O solute element, of twenty Cu-base metallic systems containing Ce or Y and S, O,S+O, Al, Si, Pb, Sn, Zn, Ti, Fe solute element respectively, of ten Al-base metallic systems containing Ce and Mg, Ti, Mn, Zn, Fe, Sn, Pb, Ni, Cu, Si, S solute element respectively were determined by different experimental meth0ds according to the cheracter of systems. The dynamic parameters between rara earth addition agents and S, O, N, H in iron-steel liquid solutions and the data for the effect and application of rare earths in more twenty alloys were obtained. These results of author's group provide a basis for explaining summarily some physic-chemistry effect of rare earth elements on metals and alloys.

This article presents a review on the development condition of metal matrix composites (MMCs), includes its recent situations, varieties, production techniques, applications and existent problems. Some researching topics with great demand such as interface structure and behaviours, solidification, manufacturing science on some popular varieties of MMC and in situ technologies are also involved. On the base of these situations, a future development view is prospected.

The attractiveness of the science and technology of titanium based materials makes them an important and fundamental levering factor in the high-technology era. Competition in the technology of titanium based materials has become increasingly severe with the worldwide high-technology development. This paper analyses the developing strategies and measures adopted to develop titanium based materials by the United States, Japan and Western Europe, and summarizes their successful experiences and lessons to be 1earned. On the basis of this analysis and by taking into account the status quo of China, the strategic goals and appropriate measures for the development of titanium science and technol0gy in China are proposed within the framework of the general strategies of "strengthening by science and education" and "rapid modernization". It is suggested that the traditional titanium based industries should be innovated along with the development of an independent and self sustaining industry of high-technology titanium based materials. The measures that should be adopted to realize these goals are discussed in detail.

The deformation-induced martensitic transformation and its reversibility in Ni-Ti-Nb alloys have been studied by means of tensile test at various temperatures, electrical resistance measurement, TEM and HREM observations. The relationship between the stability and reversibility of deformed stress-induced martensite and its variant interface structure was analyzed. It is shown that stress and strain induced martensitic transformations occur,respectively, when Ni-Ti-Nb alloys are deformed between Ms and Ms temperatures and above Ms temperatures. The deformation has obvious effect on interface structure of stress-induced martensite. The interface of stress-induced martensite (SIM) is straight and well-defined as well as perfectly coherent. However, ledges and distorted layers are formed in the interface of SIMs subjected to low deformation strain and the interfacial coherence is damaged to some extent. With the increasing of deformation strain, the ledges and distortedlayers gradually turn into the confused layers and the interfaces of martensite variants completely lose coherence. Accordingly, the stability of deformed stress-induced martensite increases and its reversibility decreases with increasing tensile strain. Under the appropriate deformation conditions, the deformed stress-induced martensite subjected to suitable deformation strains has both high stability and good reversibility.

Polycrystalline materials with grains sizes in the nanometer region (typically less than 100 nm), termed nanocrystalline materials, have been intensively investigated in the past several years. Much improvement has been made in the field of both fundamental understanding and practical applications of this type of materials. This article reviews the present state of the art in this field. The current status of research and development on the synthesis,microstructure, structural instability, and properties of nanocrystalline materials will be summarized. Further consideations of the development and applications of this new class of materials will also be presented.

Recent developments in multiphase intermetallics are reviewed in this paper.The emphasis is placed upon the role various interfaces play in influencing the deformationprocess and mechanical behaviour of the multiphase alloys. The examples are taken fromTiAl based and (Ni,Fe,Co)Al based materials. It is shown that the operation of interface-related dislocation sources can improve the deformability of the brittle phases. A better balanceof mechanical properties can be obtained when the beneficial effects of the interfaces are manifested by a proper choice of constituent phases and conditions of material preparation andprocessing.