钛合金的超高周疲劳滑移-解理竞争失效机制  

Evaluation of Slip-cleavage Competition Failure Mechanisms for Titanium Alloys Induced by Microstructure in Very-high-cycle Fatigue Regime

作　　者：杨溥 邓海龙[1,2] 康贺铭 刘杰[1] 孔建行 孙宇凡 于欢[1] 陈雨 YANG Pu;DENG Hailong;KANG Heming;LIU Jie;KONG Jianhang;SUN Yufan;YU Huan;CHEN Yu(School of Mechanical Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;Key Laboratory of Inner Mongolia for Advanced Manufacturing Technology,Inner Mongolia University of Technology,Hohhot 010051,China)

机构地区：[1]内蒙古工业大学机械工程学院,呼和浩特010051 [2]内蒙古工业大学内蒙古自治区先进制造技术重点实验室,呼和浩特010051

出　　处：《材料研究学报》2024年第7期537-548,共12页Chinese Journal of Materials Research

基　　金：内蒙古自治区自然科学基金(2022MS05014,2021LHMS05009);内蒙古高等教育研究项目(NJZY21306);内蒙古自治区区直属高校基本科研业务项目(20220233);内蒙古工业大学科学研究项目(ZY202005)。

摘　　要：对TC4钛合金进行应力比为-1、-0.3和0.1的室温超高周疲劳实验,研究了微结构导致的超高周疲劳滑移-解理竞争失效机制。结果表明,这种合金的S-N曲线均呈双线性,表现出表面滑移失效、表面解理失效和内部解理失效三种失效模式。采用GP极值分布函数明确了表面缺陷尺寸的分布特性,并将其定义为试样表面区域厚度。计及试样的控制体积、外载荷大小、α晶粒含量以及α晶粒尺寸等微结构的耦合影响,将σ_(max)值的增大或减小作为TC4钛合金疲劳失效模式转变的主要因素构建了竞争失效模型。结果表明,所建模型的预测结果与实验数据有较好的相关性。用控制变量法研究了W值、α晶粒尺寸和α晶粒含量对TC4钛合金滑移-解理竞争失效机制的影响,发现W的取值并不影响表面滑移失效概率,α晶粒的增大或α晶粒含量的降低均有利于TC4钛合金的表面滑移失效;较大的W值、较大的α晶粒尺寸以及较少的α晶粒含量均有利于TC4钛合金的表面解理失效;较小的W值、较大的α晶粒尺寸以及较少的α晶粒含量均有利于TC4钛合金的内部解理失效。In order to comprehensively evaluate the influence of alloy structure on the competition mechanism of slip-cleavage failures during ultra-high cycle fatigue process of Ti-alloy,a competition failure model considering the maximum stress(σ_(max))was constructed,and then the competition mechanism among failure modes was quantitatively described.Furthermore,the influence of microstructure(surface defects,αα-grain size andα-grain content)on the competition mechanism was revealed in detail by means of the control variable method.Meanwhile,ultra-high cycle fatigue tests of TC4 Ti-alloy under stress ratios of-1,-0.3 and 0.1 were carried out at room temperature.The S-N curves obtained under three stress ratios were bilinear,and TC4 Ti-alloy showed three failure modes,namely surface slip failure,surface cleavage failure and internal cleavage failure.The GP extreme value distribution function is used to clarify the distribution characteristics of the surface defect size,and the predicted extreme size of the surface defect is 5.69μm,which is defined as the thickness of the sample surface area.Next,the coupling effect of microstructure variables such as control volume,external load,α-grain content andα-grain size,the increase or decrease ofσ_(max)value is taken as the main factor of fatigue failure mode transformation of TC4 Ti-alloy and the competitive failure model is constructed.The calculation results show that the model prediction results have a good correlation with the experimental data.Finally,the effect of W value,α-grain size andα-grain content on the slip-cleavage competition failure mechanism of TC4 Ti-alloy was investigated by the control variable method.It is concluded that smaller W value,largerα-grain size and lessα-grain content are beneficial to the internal cleavage failure of TC4 Ti-alloy.The value of W does not affect the probability of surface slip failure,and the increase ofα-grain size or the decrease ofα-grain contentis beneficial to the surface slip failure of TC4 Ti-alloy;The smaller W

关 键 词：金属材料 超高周疲劳 失效机理 TC4钛合金 滑移-解理 竞争失效 

分 类 号：TG131[一般工业技术—材料科学与工程]