摘要
Twinning is an important deformation mechanism in engineering materials,which can improve the ductility and strength of alloys,especially in the case of low-plasticity Ti Al alloys.Herein,a large number ofγtwins,twin intersections and adjoining twin pairs(ATPs)are formed in globularγ(γ-glob)phase after high-temperature tensile deformation.The ATPs consist of two sets of deformation twins(DTs)that are mirror symmetric about the original twin boundary(OTB).Its formation mechanism is analyzed with electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results reveal that the ATPs are related to the strain coordination between the DTs and the adjacent grains.Specifically,as the DT is formed in theγ-glob and impinges on the OTB,it will induce anotherγtwin(IT)in the adjacentγ-glob.The combination of the twoγtwins generates ATPs,which are formed by the transmission of a twin from one grain to the neighboring grain.Moreover,γtwins with a lower Schmidt factor(SF)of 0.2643 are preferentially formed over anotherγtwin with a higher SF(0.3098)in the sameγ-glob grain,becauseγIT accommodates the strain caused by theγDT in adjacent grain.Besides,the long-period stacking ordering(LPSO)structure of periodic contrasts 1(PC_(1))and PC_(2)are observed inγtwins,which are considered to be the intermediate phase for the formation ofγtwins.The current work elucidates the formation mechanism of ATPs in Ti Al alloy and provides insights into the formation of twins in theγ-glob.
基金
financially supported by the National Natural Science Foundation of China(No.52174377)
the China Postdoctoral Science Foundation(No.GZC20240524)
the China Postdoctoral Science Foundation(No.2024M750998)
the National Key Research and Development Program of China(No.2021YFB3702603)
the National Natural Science Foundation of China(NSFC)(No.51371049)。
