含铜抗菌不锈钢拉伸过程中的微观组织演变EBSD分析

EBSD Analysis of Microstructure Evolution of Copper-containing Antibacterial Stainless Steel during Tensile Process

目的研究含铜抗菌不锈钢拉伸性能,为工业生产中的成形工艺优化提供一定的理论依据。方法在拉伸应变分别为5%、15%、30%、45%、60%、75%以及最后拉伸断裂时应变为81%条件下,采用岛津AGS-100KN万能拉伸试验机对含铜抗菌不锈钢进行拉伸试验。通过扫描电子显微镜(SEM)、电子背散射衍射仪(EBSD)和透射电子显微镜(TEM)表征分析含铜抗菌不锈钢拉伸断裂后的断口形貌以及拉伸过程中的微观组织演变。结果含铜抗菌不锈钢抗拉强度最大值为587.523 MPa,应变最大值为81%。拉伸断口与拉伸方向呈45°开裂,呈杯锥状,断裂模式是韧性断裂。结论随着应变的增大,低角度晶界逐渐增多,高角度晶界与孪晶逐渐减少,GOS值逐渐增大,Goss织构、S织构和R织构含量逐渐减少,Brass织构含量逐渐增加,拉伸断裂后的体积分数为23.3%。在拉伸后期,Copper织构和Brass织构含量较多,在拉伸过程中起到整体稳定协调微观组织作用的S织构不断减少,随应变的增大,组织内部协调变形加快,变形程度快速增大,从而导致S织构向Copper织构和Brass织构转变,出现板条状马氏体,存在应变诱发马氏体相变。位错滑移、形变孪晶和形变诱导马氏体等多种变形机制的共同作用使含铜抗菌不锈钢具有良好的塑性。

The work aims to study the tensile properties of copper-containing antibacterial stainless steel,so as to provide a theoretical basis for the optimization of forming process in industrial production.The tensile test of copper-containing antibacte-rial stainless steel was carried out by Shimadzu AGS-100KN universal tensile testing machine at tensile strains of 5%,15%,30%,45%,60%,75%and 81%,respectively.The fracture morphology and microstructure evolution of copper-containing anti-bacterial stainless steel during tensile process were analyzed by scanning electron microscope(SEM),electron backscatter dif-fraction(EBSD)and transmission electron microscope(TEM).The maximum tensile strength of copper-containing antibacterial stainless steel was 587.523 MPa,and the maximum strain was 81%.The tensile fracture was cracked at 45°with the tensile di-rection,showing a cup-cone shape,and the fracture mode was ductile fracture.With the increase of strain,the low-angle grain boundaries gradually increase,and the high-angle grain boundaries and twins gradually decrease.GOS value increases gradually.The content of Goss texture,S texture and R texture decrease gradually.The content of Brass texture increases gradually,and the volume fraction after tensile fracture is 23.3%.In the later stage of stretching,there are more Copper texture and Brass texture.During the tensile process,the overall stable and coordinated S texture of the microstructure continues to decrease.With the in-crease of strain rate,the coordinated deformation inside the microstructure accelerates,and the degree of deformation increases rapidly,resulting in the transformation of S texture to Copper texture and Brass texture.Martensite appears,and there is strain-induced martensitic transformation.The combination of various deformation mechanisms such as dislocation slip,defor-mation twins and deformation-induced martensite makes the copper-containing antibacterial stainless steel have good plasticity.