Effect of cross rolling on the microstructure and mechanical performance of a dual-phase structured Mg-8Li-6Zn-1Y(in wt.%)alloy

The microstructure and mechanical performance of the unidirectionally and cross-directionally rolled Mg-8Li-6Zn-1Y(in wt.%)sheets have been investigated and compared.It reveals that after the unidirectional rolling(UR),the broken I-phase particles are aggregated at theα-Mg/β-Li phase interfaces.However,the cross-rolling(CR)process can not only severely break the bulk I-phase,but also cause the obviously uniform distribution of I-phase particles in the matrix phases.Moreover,the average grain size of the CR samples is 3.61μm and about 50%that of the UR samples.The maximum texture intensities ofα-Mg andβ-Li phases in the CR samples are slightly stronger than those in the UR samples.Tensile results demonstrate that the CR process can effectively enhance the tensile properties and remarkably reduce the mechanical anisotropy of the alloy.For the UR samples,the yield strength,ultimate tensile strength,and elongation ratio along the rolling direction(RD)are 164 MPa,198 MPa,and 16.4%,whereas those along the transverse direction(TD)are 157 MPa,185 MPa,and 22.0%,respectively.For the CR samples,their mechanical properties are basically the same and the mechanical anisotropy is almost eliminated.The yield strength,ultimate tensile strength,and elongation ratio along the cross-rolling direction 1(CRD1)and 2(CRD2)are respectively measured to be 181 MPa and 182 MPa,220 MPa and 218 MPa,20.6%and 20.7%.Failure analysis indicates that for the UR samples being tensile tested along the RD and TD,microcracks are preferentially initiated in the region of aggregated I-phase particles.For the CR samples being tensile tested along both two cross-rolling directions,the initiation of micro-cracks mainly occurs at the I-phase/matrix phase interfaces and in the interior of matrix phases.

Microstructure and Mechanical Properties of Cross-rolled Ti_(50)Ni_(47)Fe_3 Shape Memory Alloy

The microstructures, the phase transformation characteristics, and the mechanical properties of the Ti50Ni47Fe3 alloy in as-forged and as-cross-rolled states were investigated. It is found that, after cross-rolling, the phase transformation temperature （Ms） of the alloy decreases drastically and the grains get refined. Moreover, its yield strength and fracture strength after cross-rolling hit 540 MPa and 687 MPa respectively, up by about 200 MPa over those in as-forged state.

Evaluation of stress intensity factors of thin AZ31B magnesium alloy plate under biaxial tensile loading

Stress intensity factors of thin AZ31B magnesium alloy sheet under biaxial tension loading were analyzed by modified Dugdale model. K-values with crack angle of 90° obviously show that there is no influence of the loading condition in Mode-I. In the 45° case, K1 values are obtained within 10% errors when they are calculated by modified Dugdale model under biaxial loading. It is concluded that the modified Dugdale model is one of effective ways to evaluate stress intensity factor of AZ31 magnesium alloy sheet appropriately.

Spillover and crossover from work overload to spouse-rated work-to-family conflict:The moderating role of cross-role trait consistency

While most previous research in social psychology shows benefits of individuals’consistency in personality across different social roles,the current study brings the concept of cross-role trait consistency to the context of management and examines its dark side.Data from 197 couples showed that an employee’s work overload was positively associated with his/her spouse’s perception of how much the employee’s work interfered with family life.This relationship was mediated by the employee’s job burnout.More importantly,this mediating relationship was moderated by the employee’s cross-role trait consistency.These findings indicate that work overload may affect spouses’perception of employees’work-to-family conflict through job burnout,with the transmission of burnout on work-to-family conflict stronger among employees high in cross-role trait consistency.Thus,cross-role trait consistency appears to strengthen negative spillover and crossover from work to family.Theoretical and practical implications are discussed.

Regulating the recrystallized grain to induce strong cube texture in oriented silicon steel

Cube texture contains two easy magnetization directions<001>parallel to rolling and transverse direction,respectively,which is the most ideal magnetic texture suitable not only for transformers but also for rotating machines.In this study,a strong cube texture with ODF density of 50.73 mrd was successfully obtained by regulating the recrystallized grain orientation using cross-rolling and pulsed electric current,compared to conventional thermal annealing(the average cube texture intensity is~10 mrd in lots of latest studies).Cross cold rolling process intentionally"created"metastable deformed cube orientation in oriented silicon steel and the specific recrystallization texture rotation path was identified under pulsed electric current in 5 min:{114}<261>→{114}<151>→{114}<041>→{001}<150>→{001}<010>.The cube-oriented grains were induced by pulsed electric current(800℃)and rapid heating(51.9℃/s,750℃),while the cube grains were observed in the annealed samples at the high temperature(1060℃).Recrystallized grain size of pulsed samples is about twice that of the annealed sample.This phenomenon is considered that the concurrent effects of electron wind force and Joule heating affected the nucleation,growth and rotation of cube grains by reducing the nuclear barrier,producing higher grain boundary mobility and structural evolution towards a state with lower electrical resistance.This idea of current-controlled texture is worthy of popularization in more materials and the realization of an electromagnetic field to crystal orientation selection is an interesting topic.

Texture Evolution and Ultrafine Grain Formation in Cross-Cryo-Rolled Zircaloy-2

The texture and mechanical properties of cross-rolled zircaloy-2 at 77 and 300 K were investigated.Crossrolling at 77 K was performed to impart different thickness reductions of 25% and 50%,while at 300 K with 25%,50%,75% and 85% reductions to the sample.EBSD analysis of deformed sample showed that near-basal orientation is not deformed completely after 50% rolling reduction.The activation of prismatic silp,{1122} contraction twin and {1012} extension twin were evident from the deformed microstructure at 77 K.The propensity for activation of basal slip〈a〉 at77 K was also observed.The deformation of the sample at 300 K occurs by prismatic,basal 〈a〉 and pyramidal 〈c＋a〉slips,which were predicted by pole figures.After annealing,the tensile strengths（735 and 710 MPa） are almost the same for 50% cryo-cross-rolled and room-temperature cross-rolled zircaloy-2 with almost 2.7% difference in their ductility.KAM analysis of the deformed samples was made to estimate the stored strain energy and dislocation density.Annealing of deformed sample at 673 K for 30 min results in recrystallization,which leads to the formation of ultrafine grains.