Large Deformation Arb Prepares Ultrafine Grained Copper Texture Organizations Evolution

Analysis methods of X-ray diffraction pole figures, of orientation distribution function(ODF) and of residual stress have been improved. Evolvement of severe plastic deformation textures and recrystallization textures of copper processed by accumulative rolling bonding (ARB) and characteristics of textures of metal materials with cube structure have been researched in this paper. Some results are listed as following:1. A mathematics method has been established which can calculate any plane's ideal pole figures of a certain texture. According to this method, many pole figures of some usual deformation textures and annealing textures have been calculated.2. A mathematics method has been set up which can calculate taking part in the slide system and Schmidμof FCC metal materials with the results of textures.3. A residual stress analysis of X-ray diffraction has been established using texture attachment without special residual stress attachment and software.4. Analysis method of ODF without the powder reference sample has been brought forward which is validated by experiments. K values of many powder reference materials used for scattering focus correction are similar, which is foundation of ODF analysis without powder reference samples.5. Checking computation method of ODF's results has been set up.6. Evolvement of microstructure textures of copper processed by severe plastic deformation ARB has been discovered.When pass number of ARB is equal to or more than 6 (true strain≥4.2), deformation texture of copper surface processed by AARB is{100}<011>shear texture, the intensity of shear texture near surface is obviously more than that of surface, and there is{211}<111> copper texture in inner of the sample. Deformation texture of copper sample's surface and inner processed by NARB is{211}<111> copper texture, the intensity of copper texture near surface is obviously more than that of surface too. Intensity of copper texture of the sample's inner processed by AARB or NARB is uniformity, and distribution of texture along center layer through thickness is symmetrical. Texture components and intensity of texture fail to vary when true stain is from 4.2 to 6.93. It indicates that shear texture and copper texture of copper sample are stable when they are processed by SPD ARB.Annealing textures of copper processed by SPD ARB change during heat treatment. On the first stage of annealing(240-260℃×1h),there are dominant{112}<111> and {100}<011> deformation textures and{111}<211> annealing texture in copper sample. On the middle stage of annealing(280-340℃×1h),{112}<111> and{100}<011> deformation textures have already disappeared and there are some{111}<211> annealing texture and recrystallization cube textures, On the last stage of annealing(380-600℃×2h), there is only cube texture in copper sample processed by NARB and there are cube texture and {221}<122> texture in copper sample processed by AARB. Shear texture{001}<110> may be responsible to formation of{221}<122> recrystallization texture.That interface of adjacent two layers confines deformation range of grains affects remarkably development of textures. It is not necessary for true strain to increase unlimitedly in ARB processing. There is a critical strain which deformation texture of grains is attained utmost state. With increasing strain during ARB processing, hardness of copper fail to increase continually which approaches saturation value, and grains size, dislocation densities, microstrain, crystal lattice constants of copper samples approaches saturation value too. It indicates that improvement of performances of metal materials processed by SPD is limited.7. Characteristic of textures of metal materials with cube structure has been discovered by experiments.There is commonness in directional cohesion, chemical vapor depositing (CVD), ion sputtering and galvanizing and so on 4 kinds of crystal growth. Direction of cubic crystal growth along normal direction of substrate is<111>or<100>, and direction of cubic crystal growth on the plane parallel to substrate is random. For example, CVD Ta's texture is <100>//ND, electrodepositing Au's texture is (100)//ND or (111)//ND, and ion sputtering Ag and its annealing(500℃×1h) state's textures are (111)//ND.Deformation textures of forged, extruded and drawn cubic metals are the same fibre textures which include<100>//axis,<110>//axis and<111>//axis and so on. After annealed, fibre textures of samples fail to change and even become stronger. For example, deformation (98% strain) texture and annealing (600℃×2h) texture of forged pure copper are all<110>//axis textures of which intensities are very similar.Annealing recrystallization textures of rolled pure metals are generally different from original deformation textures. However, Annealing recrystallization textures of rolled alloys are almost the same as original deformation textures because alloys elements fix deformation textures. For example, rolling texture of pure copper is{211}<111> copper texture which final annealing recrystallization texture is{001}<100>cube texture, and annealing textures are the same as rolling textures which are dominant{110}<112> brass textures when AgCu28 alloy is annealed at 650℃for 1.5h.Anisotropy of atom arrangement of metals materials induces anisotropy of properties.Ultimate tensile strengths along transverse direction (TD) are bigger than those along rolling direction (RD) in metals with{110}<112> brass texture. For example, ultimate tensile strengths of the deformed AgCu28 alloys are 750MP along TD and 680MPa along RD respectively, and ultimate tensile strength of the annealed AgCu28 are 374MPa along TD and 327MPa along RD respectively.