TWIP不锈钢层错能计算、塑韧性和耐蚀性能研究  

Study on stacking fault energy calculation, plastic toughness and corrosion resistance properties of TWIP stainless steel

作　　者：曾泽瑶 杨钢[2] 杨银辉[1] 龚志华[2] ZENG Zeyao;YANG Gang;YANG Yinhui;GONG Zhihua(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;Institute for Special Steel,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《钢铁研究学报》2021年第5期443-451,共9页Journal of Iron and Steel Research

摘　　要：添加Cr元素设计具有形变诱导孪生效应(twinning-induced plasticity, TWIP)的高强不锈钢,采用亚点阵晶格模型运用Matlab计算得到设计合金层错能(stacking fault energy, SFE)为37.65 mJ/m^(2)。通过(900~1 200)℃×1 h热处理发现晶粒尺寸、退火孪晶数量、初始晶粒尺寸和孪晶片层厚度均随着固溶温度的升高而增加;观察拉伸断口剖面发现在大晶粒中形变孪晶数量多相互交错程度高,形变孪晶不断切割奥氏体晶粒使得材料发生大的无颈缩延伸,应变硬化平台(θ=0)出现较早,随着应变增大,高固溶温度下的混晶组织使得该平台呈交替出现。固溶温度从900℃升高至1 200℃,原始奥氏体晶粒尺寸由25.1μm增大至64.91μm时,冲击吸收功由231 J减少至202 J,断裂方式为韧性断裂,强塑积由47 GPa·%增至69 GPa·%。通过动电位极化曲线分析实验钢在3.5%(质量分数)NaCl中的具有相对较低的腐蚀电位(E_(corr)=-302 mV)和腐蚀电流密度(I_(corr)=1.03×10^(-6) A/cm^(2)),观察分析夹杂物容易成为点蚀诱发源,腐蚀过后观察到其表面产生大量的腐蚀坑洞。High strength stainless steel with twinning induced plasticity(TWIP)was designed by Cr element addition.According to the sublattice lattice model,Matlab software was used to calculated the stacking fault energy(SFE)of the designed alloy is 37.65 mJ/m^(2).The number of annealing twins,the initial austenite grain size and the thickness of twin all increased with the solution treated temperature range of 900-1200℃.The tensile fracture profile microstructure shows that high interleaving degree with deformation twins in the large grains and continuous segmenting of prior grains by deformation twins resulting in large neckless elongation.The strain hardening platform(θ=0)appeared relatively earlier with the strain increased,then with high temperature solution treated the mixcrystal structure makes the platform appear floating.The prior austenite grain size increased from 25.1μm to 64.91μm with the solution temperature increased from 900 to 1200℃,which lead to the impact absorption energy decreased from 231 J to 202 J,and the fracture way is micro pores aggregation ductile fracture and the product of strength and ductility increased from 47 to 69 GPa·%.The corrosion potential(E_(corr)=-302 mV)and corrosion current density(I_(corr)=1.03×10^(-6) A/cm^(2))of the experimental steel were analyzed by potentiodynamic polarization curve in 3.5 wt%NaCl solution.It is observed that inclusions are easy to become the pitting induced source,and a large number of corrosion pits are observed on the surface after corrosion test.

关 键 词：TWIP效应 层错能 晶粒尺寸 吉布斯自由能 

分 类 号：TG142.71[一般工业技术—材料科学与工程]