Research On Pulsating Electric Current Effect Of Synthesis And Deformation Of Ni/Al And Ti/Al System Intermetallic Compound

Being a new generation of high temperature structure materials, Ni/Al and Ti/Al system intermetallic compounds are most potentially. They possess many excellent capabilities at high temperature such as high strength, corrosion resistance, contrast intensity and contrast rigidity. But a lot of information show that their properties of cutting and deformation are very dissatisfactory. At present there are some problems in SHS researches of Ni/Al and Ti/Al system intermetallic compound such as lack of detail description of reaction characters, low density of SHS products, dissatisfactory in precision of shapes and sizes, difficult in practical manufacture.Subsidized by the National Natural Science Foundation of China, "Tenth Five-year" Plan of Hubei province and so on, this dissertation systematically discussed the author's researches on synthesis and deformation of Ni/Al and Ti/Al system intermetallic compound. The major contents and innovation of the research are listed as following:The organization and structure reasons of low plasticity of Ni/Al and Ti/Al system intermetallic compound at room temperature are analyzed. The measure of grains' comminution is brought forward to improve plasticity at room temperature. The key of micro-crystal's production is that the time of sample's being at high temperature is shorter. The process of crystal's growing up will be restrained.The preparation and activation methods of machine milling (MM for short) for Ni/Al and Ti/Al system tiny powder are researched. The technical treatment of MM makes metal powder a lot of changes in mechanical properties, chemical properties and organization structure. An arithmetic solution of comminution rule for pure metal powder in MM is put forward and then used to calculate the processes of pure metal powder such as Ni and Fe in MM. The effects ofdifferent MM parameters to different materials such as Ni powder, Al powder, Ti powder, Ni/Al powder, and Ti/Al powder are researched.The processes and characters of synthesis reaction for Ni/Al and Ti/Al under the influence of lower pulsating electric current are researched. Reasonable technology of MM will make the organization and micro-hardness of synthesis products more uniformity. The treatment of pulsating electric current at room temperature can break up oxidation surface of grains and improve the conditions of reaction. The effects of pulsating amounts, pulsating time, height of sample, pressure to rising speed of temperature, Tig and Tmax, pulsating sensitivity, and density of products are analyzed.The processes and characters of synthesis reaction for Ni/Al and Ti/Al under the influence of high intensity of pulsating electric current are researched. The characters of organization and structure of products under different parameters such as charge voltage, charge capacitance, pulsating electric current, pulsating amounts and pulsating duration are summarized. The input energy of sample is calculated. Some discovers are made in research. The reactions are concentrated in interface and the components of reaction areas are grads distributed.Thermodynamics parameters of Ni/Al and Ti/Al system intermetallic compound are analyzed and calculated. The macro temperature rising velocity of powder sample under the influence of high intensity of pulsating electric current are calculated. An arithmetic solution of micro temperature rising velocity of powder sample under the influence of high intensity of pulsating electric current are brought forward. Upon the foundation of contracted-ball, function equations of conversion rates of grains and time are deduced. It is brought forward that the conversion rates of grains rely on reaction velocity at interface and diffusion velocity in reacted layer and at the same time relate to reaction process.The diffusion processes of samples are analyzed. The effects of high intensity of pulsating electric current are discussed. It is found that the interfacediffusions are dominant under the influence of high intensity of pulsati...