Laboratory experiments demonstrate that the magnetic-beneficial {100} texture can be strongly produced using the so-called surface effect transformation treatment either in low-grade electrical steels or in high-grade 3%Si steels. In the latter case, the solid-phase transformation is introduced into Si steels by adding carbon and manganese elements. In addition, vacuum annealing and subsequent wet hydrogen decarburization are needed. Although such treatment differs remarkably from conventional industry production facilities, its superiority of producing extremely sharp {100} texture, immensely high magnetic induction, and low core loss keeps the method attractive for environmental friendly and high efficiency rotating machines. Our previous results indicated that the heavy rolling reduction favors the rotated cube texture {100}< 011 > formation; however, the cube texture {100}< 001 > is expected due to the easiness of sheet cutting for iron core production in the industry. In this study, the influences of compositions on the formation of the cube texture, 25-rotated cube texture, and rotated cube texture were investigated. The phase diagram features of the alloy consisting of strong cube texture were also examined. The aim is to establish the theoretical bases for quantitative control of the alloy composition suitable for cube texture in 3%Si electrical steels. Four steel compositions are designed using different combinations of carbon and manganese contents. Thus, the transformation temperatures, ferrite grain sizes, and pearlite volume fractions will be different, leading to distinct growth rates of {100} oriented grains during vacuum annealing at a constant temperature. They were cold-rolled by 50% reduction, which is beneficial for the cube texture formation. The results of experimental determination and calculated phase diagrams indicate that the alloy with lower carbon and Mn contents in the investigated four steel compositions shows a faster and stronger cube texture in the Mn-removal surface layer. The area fraction of the {100} texture in the Mn-removal layer of the alloy after vacuum annealing at 1100 C for 30 min reaches 77.3%. In addition, the suitable decarburization temperature after the formation of the Mn-removal surface layer is discussed and suggested based on the calculated phase diagrams.

The deformation-induced transformation characteristics and texture evolution of α′-martensite during cold rolling together with the tensile properties of two specially prepared initial microstructures (bimodal elongated γ grains and fine equiaxed γ grains) were investigated in high manganese TRIP steels. The results showed that the thermally induced martensite was restrained effectively by refining grains or introducing crystal defects like dislocations, which provided a nearly full austenite phase for the subsequent TRIP process. Compared with the solution-treated sample containing coarse equiaxed γ grains, the fine-grained sample revealed a better plasticity and a higher strength due to grain refinement and progressive TRIP process. The bimodal elongated-grained sample exhibited the highest strength and sufficient plasticity because the dislocation strengthening exceeded the fine-grain strengthening and martensitic transformation was delayed. The transformation textures of two kinds of samples differed in that the fine-grained sample demonstrated typical {113}<110>α from the Copper-type γ texture and {332}<113>α from the Brass-type γ texture, whereas {001}<110>α texture occurred in the bimodal elongated-grained sample in addition to the above two components. In the early stage of TRIP, there was an obvious orientation dependence, and the {100}- and Copper-oriented γ grains preferentially transformed to martensite rather than γ grains with Brass orientation.

The microstructures and textures of the non-oriented electrical steel sheets under various annealing conditions were investigated.The orientation gradient in the interior of grains appeared on the surface of steel sheets after α → γ → α transformation in various atmospheres.The orientation gradient that appeared on the surface was inherited into the center of the steel sheet in H2 atmosphere,while that appeared only in the grains of the surface layer during γ → α transformation with N2 atmosphere.The thin oxide scale was generated in various atmospheres containing traces of O2 and H2O.The formation mechanism of orientation gradient is related to the thermal stress caused by the difference of thermal expansion coefficients between the oxide scale and the thin ferrite on the surface.The combined effect of phase transformation stress and thermal stress caused the plastic deformation of the thin ferrite grains on the surface in the initial stage of γ → α transformation,and then the orientations of the thin ferrite grains gradually rotated and caused the orientation gradient in the interior of grains.

To meet the requirement of environment, economy and safety, advanced high strength steels including dual phased (DP), complex phased (CP), transformation- induced plasticity (TRIP) and twinning-induced plasticity (TWIP) steels are widely used for automotive steel. Among them, high manganese TWIP and TRIP steels are particularly appealing due to their outstanding tensile strength and elongation. In contrast to high manganese TWIP steel, high manganese TRIP steel exhibits higher strength and work hardening rate due to strain induced martensitic transformation. The enhanced mechanical properties of high manganese TRIP steel are determined by both the stability of the retained austenite (gamma) and the initial microstructure. Strain induced martensitic transformation and subsequent reversion from deformed martensite to gamma during annealing is often applied as one of the most effective methods for microstructure improvement. Microstructure and texture characteristics of high manganese TRIP steel during cold rolling together with the reversion of deformed bcc martensite (alpha'-M) at high temperature were investigated. It is shown that the gamma was almost completely transformed into alpha'-M at medium cold rolling reduction. And a higher reduction after alpha'-M saturation resulted in dominantly the deformation of alpha'-M, hence thin laths paralleled to the rolling direction (RD) were obtained. The main components in alpha'-M were {113}< 110 >, {554}< 225 > and rotated cube ({001}< 110 >) textures at medium cold rolling reduction, which are the typical phase transformation textures. The {113}<110> texture rotated toward a more stable orientation {223}< 110 > and led to a strong cold rolling texture (< 110 >//RD) with increasing reduction. The reversion of martensite and recrystallization of gamma proceeded at temperature ranging from 650 degrees C to 850 degrees C. The reversion of alpha'-M proceeded in a diffusional mechanism, accompanying with the redistribution of Mn and Al between gamma and alpha'-M. Deformed alpha'-M was merged by the adjacent gamma, and columnar gamma grains with a large amount of subgrains were obtained. The texture of reverted gamma was approximately the same as that of the deformed gamma, this phenomenon called texture inheritance was formed by the direct growth of gamma. Subsequently, recrystallization of gamma grains occurred by sub-grain coalescence and the columnar g grains were instead by equiaxed gamma grains.

The texture evolution of cold rolled pure titanium through different annealing parameters was investigated and different processes for various textures controls were proposed for further industrial application. Columnar grains with strong {11–20}//RD (rolling direction) texture was produced through cold rolling and a cooling-controlled annealing at 1100 °C with the Ar atmosphere. The preferred nucleation on the surface and the lowest strain energy of variant pairs during grain growth caused the formation of columnar grains and variant selection. Texture inheritance was discovered both in the cold-rolled and warm rolled-pure titanium sheets following 1000 °C annealing. The stored energy during cold rolling was the main reason causing the texture inheritance. Basal texture could be produced through warm rolling and subsequent annealing. The 30°-rotated around RD from basal texture could be preserved through both recrystallized annealing and transformed annealing.

The excellent combination of strength and elongation and the super work hardening behavior of high manganese TRIP/TWIP(transformation-induced plasticity/twinning-induced plasticity) steels are due to the presence of two kinds of martensitic transformations and their complicated interactions of three phases during deformation.This work investigated the crystallographic characteristics ofγ→e→α' transformation,and in particular,the effects of deformation twins and austenitic grain orientations on martensitic transformation by means of EBSD technique.Results showed thatα'-martensite was triggered at the intersection of twoe-martensite variants.Deformation twins were frequently detected neare-martensite,thus twins promoted the formation ofe-martensite and played an important role during TRIP process.However,twinning was affected by austenite grain orientations.It is suggested that austenitic grain orientations with low indices,such as {100},{111} and {110},more easily promoted the intersection ofe-variants due to the multi-twinning and thus facilitated furtherα'-martensite formation than those with high indices.Deformation increased the number ofevariants but reduced their sizes and therefore it is difficult for the small strain-inducede-martensites to transform intoα'-martensites smoothly.

In this paper, deformation behaviors of two kinds of martensites (hexagonal and bcc structures) and the influence of austenitic orientations on martensitic transformation in high manganese TRIP/TWIP (transformation-induced plasticity/twinning-induced plasticity) steels during compression were analyzed by EBSD technique. Results showed that, in hexagonal martensites low angle grain boundaries caused by slip and special misorientations such as 93 degrees < 7 (2) over bar(5) over bar3 > were detected in addition to those inherited due to orientation relationship. In bcc martensite, low angle misorientations due to slip were dominant in addition to the special misorientations between alpha'-M variants or those inherited from austenitic twins. Besides, austenitic orientations affected phase transformation and it was observed that martensite was induced faster in austenitic grains of {110}(gamma) orientation than that of {100}(gamma) orientation. alpha'-M orientation changed more obviously in {110}(alpha') oriented grains because they were unstable during compression. The reasons for the formation of new special misorientations in hexagonal martensite and the influence of austenitic orientation were discussed.

The secondary recrystallization and its temperature range of grain oriented silicon steel have been studied by the method of interrupting secondary recrystallization annealing.The evolution of grain sizes and grain orientations during the slow heating process was determined by EBSD technique.The Goss oriented grains,their grain sizes and their misorientations to the surrounding grains were analyzed.The effects of grain boundaries with high energy or high mobility and surface atmosphere on the growth of Goss grains are discussed.

Due to the poor plasticity of magnesium alloys at room temperature(about 15%), twinning plays an important role in the deformation of magnesium alloys,and twins will be the dominant recrystallization nucleation sites.There are at least two types of twinning in magnesium:the {10(?)2}-type tension twinning and the {10(?)1}-type compression twinning.Tension twinning proceeds much more easily than compression twinning since its volume fraction is much higher than that of compression twins,which may have a promotion effect on the recrystallization to a certain degree. Based on the previous research on the static recrystallization at compression twins,the evolution of microstructure and texture in AZ31 magnesium alloy during its static recystallization at tension twins was futher investigated;and the orientational characteristics of new grains formed at tension twins in the early stage of static recrystallization were analyzed by EBSD technique.The results showed that tension twins played only a subordinate role in recrystallization nucleation and suppressed recrystallization rate,thus failed to refine grain size effectively.The strong basal texture was retained and weakened with no new texture component being detected during annealing.New grains were observed to nucleate preferentially at the intersections of tension twin variants or the intersections between tension twins and compression twins.Their orientations were relative random and are strongly scattered from those of original tension twins or compression twins.A comparison of the recrystallization at tension twins and compression twins was made.

The martensitic transformation in high manganese TRIP/TWIP steels was studied by using EBSD technique. Microstructural characteriastics of e-martensite and α-martensite were determined. The results show that austenite and e-martensite held the Shoji-Nishiyama orientation relationship of { 111 }γ( 0002 )e, 〈 10 〉γ〈 11■0 〉e, whereas e-martensite and α-martensite held the Burgers orientation relationship of (0002) e {110} α, 〈 11■0 〉e〈 11 〉α. Many α-martensite variants occurred within one austenite grain and abundant transformation twins existed between variants. A preliminery analysis on habit plane of martensites was performed.

In contrast to cubic metals, the dominant recrystallization nucleation site of hexagonal magnesium is compression twins or the shear bands evolved from them. In this paper, we determine the macrotextures and microstructures of a magnesium alloy AZ31 during static recrystallization. We interpret these data according to a microtexture analysis performed with the EBSD technique of new grains formed at compression twins in the early stage of static recrystallization. The results show that the orientation characteristics in local regions during nucleation are similar to those of subgrains within compression twins or shear bands. However, the new grains mainly take the orientations of the subgrains, which have been subjected to complicated orientation rotations. This phenomenon is attributed to the large amount of their stored energy. Despite the difference between new grain orientations and those of the deformed matrix, the retained deformation texture after annealing is explained mainly by the incomplete recrystalization of magnesium.

Stainless steel matrix composites reinforced with TiB2 or TiC particulates have been in situ produced through the reactive sintering of Ti, C and FeB. X-ray diffraction analysis confirmed the completion of reaction. The TiB2, TiC and steel were detected by X-ray diffraction analysis. No other reaction product or boride was found, indicating the stability of TiB2 and TiC in steel matrix. The SEM micrographs revealed the morphology and distribution of in situ synthesized TiB2 and TiC reinforcements in steel matrix. During sintering the reinforcements TiB2 and TiC grew in different shapes. TiB2 grew in hexagonal prismatic and rectangular shape and TiC in spherical shape.

Scanning electronic microscope(SEM) attached with related energy dispersion analysis is an important one in analysis techniques developed in recent years. Vacuum is a primary condition for ensuring the normal operation of SEM.If there was a problem in vacuum system,SEM should not be started.The behavior and its solution of a vacuum problem resulted from contamination of the pressure sensor,Penning gauge,was provided in this paper.

The reason of mis-indexing during EBSD measurement was examined based on the mis-indexing data encountered in the experiments.The materials involve HCP metal of magnesium alloys and BCC metal of electric steel.Statistical results reveal that orientation relationships of 30°〈0001〉 and 30°〈■〉 appears mostly in HCP magnesium alloys.Otherwise,30°〈111〉 is the most relationship in the BCC metal;furthermore the mis-indexing spots have CSL boundaries relative to matrix.Mis-indexing exhibits obviously orientation dependence.At the end of this article,several means of reduction misindexing are mentioned.

Orientation mapping based on EBSD technique is applied to reveal the orientation features of dynamic recrystallized grains and their neighboring matrix in a magnesium alloy AZ31 with different initial textures. The results show that, irrespective of initial texture and strain amount, new grains are similarly orientated to their neighboring matrix, illustrating a dynamic recrystallization through progressive subgrain rotation. In addition, the new grains gradually rotate to basal orientation in different samples, which indicates an important role of plastic slip during dynamic recrystallization in stead of superplastic deformation. The less subgrain boundaries in deformed grains under heavy strain were observed and these deformed grains have high quality of Kikuchi bands, which indicates that the deformed grains are consumed by the shear stress of grain boundaries parallel to the compression plane, rather than non-basal slip. The misorientation between the new and the deformed grains are measured and discussed in terms of the influence of initial texture.

The electron Backscatter Diffraction technique was used to analyze abnormal growth in Ag thin films and to determine the relationship between twinning and texture.It was found that in the presence of a 〈111〉 texture one twin boundary is parallel to the film surface.Frequent twinning did not change texture significantly,but may lead to the formation of hexagon pyramids.Each pyramid is composed of a twin pair,and its surfaces is covered by 6 {111} planes from two grains with a twin relationship.When the 〈111〉 texture is not strong further weakening of the 〈111〉 texture occurs due to twinning.

The effect of pressure, gas atmosphere and W particle size on the shrinkage kinetic curve of nano-scaled W-Cu composite powders during hot pressing were studied. The growing of W grains in W-Cu alloys was analyzed. Some mechanical properties were measured. The results show that, using composite nano-powders of W-Cu, the nano-scaled W-Cu alloy in which W particle size is not more than 0.5 μm can be obtained through hot pressing in H2 atmosphere and under a high pressure of 75 MPa at low sintering temperatures of 970-1200℃. The relative density of the ultrafine grained alloy can reach 98.8 %. The mechanical properties at 500 ℃ greatly exceed those of the conventional W-Cu alloy.

Deformation inhomogeneity in macro-scale leads to the difference in transformation and/or recrystallization, and therefore, the change in final microstructures and properties.In this paper the morphologies of deformed ferrite grains, the distribution of deformed pearlite/cementite particles and the textures in the side region and in the center of compressed low carbon steels are investigated and determined during deformation-enhanced transformation, warm and cold compression.The microstructure evolutions during transformation and recrystallization in different regions are analyzed.Results are discussed in terms of the influences of deformation stored energy, cementite particle and deformation temperature.

Ferrite (mis) orientations of Q235 plain carbon steels are determined by orientation mapping of EBSD analyzing technique. Results show that ferrite orientations are influenced by the state of austenite. Austenite dynamic recrystallization leads to a random orientation distribution of ferrite induced by strain and rather less small angle grain boundaries within ferrite grains. As the deforming temperature decreases or strain increases (111) fiber texture is strengthened and small angle grain boundaries increase, this is due to the occurrence of ferrite dynamic recrystallization. Transformation, deformation and recrystallization all contribute to the (111) fiber texture.