2D SiC_(f)/SiC中温热冲击损伤与面内剪切性能退化规律  

Thermal Shock Damage and In-plane Shear Performance Degradation of 2D SiC_(f)/SiC at Medium Temperature

作　　者：由博杰 李博 李旭勤 马雪寒 张毅 成来飞[1] YOU Bojie;LI Bo;LI Xuqin;MA Xuehan;ZHANG Yi;CHENG Laifei(Science and Technology on Thermostructural Composite Materials Laboratory,Northwestern Polytechnical University,Xi’an 710072,China;School of Materials Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China;School of Materials and Environmental Engineering,Chengdu Technological University,Chengdu 611730,China)

机构地区：[1]西北工业大学超高温结构复合材料重点实验室,西安710072 [2]陕西科技大学材料科学与工程学院,西安710021 [3]成都工业学院材料与环境工程学院,成都611730

出　　处：《无机材料学报》2024年第12期1367-1376,共10页Journal of Inorganic Materials

基　　金：航空发动机及燃气轮机基础科学中心重点项目(P2022-B-Ⅳ-002-001);西北工业大学研究生实践创新基金(PF2024004)。

摘　　要：SiC_(f)/SiC复合材料热冲击损伤是航空发动机热端部件应用中需要解决的关键问题。本研究利用全自动精准控温的热冲击设备,在1200℃测试了2DSiC_(f)/SiC的热冲击性能,拟探究热冲击损伤与面内剪切性能退化之间的相关性。结果表明,随着热冲击次数增加,2D SiC_(f)/SiC涂层表面出现硼硅酸盐玻璃(BSG)气泡,SiC基体氧化,BN界面脱黏加剧,但并未影响基体开裂、纤维桥联等损伤机制。因此,2DSiC_(f)/SiC的面内剪切应力-应变曲线依然呈双线性。热冲击产生的热膨胀失配及SiC基体氧化导致面剪模量由78.5GPa降低至63.6 GPa,面剪比例极限应力由128.9 MPa降低至99.3 MPa,面剪强度由205.8 MPa降低至187.3 MPa。根据面内剪切混合定律,BN界面脱黏加剧是剪切模量退化的关键因素。基体开裂应力公式表明,氧化后SiC基体体积分数下降,进一步降低了面剪比例极限应力。基于修正刚体块滑移模型,利用纤维台阶间距能够有效预测面剪强度的下降规律,且理论计算结果与实际值误差小于20%。Degradation of SiC_(f)/SiC composites in-plane shear performance after thermal shock represents a significant challenge for the development of hot-end components in aero-engines.In this study,thermal shock performance of 2D SiC_(f)/SiC was evaluated by using precision temperature-controlled thermal shock equipment,and correlation between thermal shock and in-plane shear performance was established.The results showed that borosilicate glass(BSG)coating caused SiC matrix forming BSG bubbles and oxidation,while BN interfacial debonding worsened with increasing number of thermal shocks.However,the thermal shock did not affect matrix cracking and fiber bridging.Furthermore,the in-plane shear stress-strain curve maintained bilinear trend.The degradation of the in-plane shear mechanism was attributed to the thermal expansion mismatch and the oxidation of SiC matrix.The in-plane shear modulus decreased from 78.5 to 63.6 GPa,the in-plane proportional limit stress decreased from 128.9 to 99.3 MPa,and the in-plane shear stress decreased from 205.8 to 187.3 MPa.According to the in-plane shear mixing rules,the degradation of shear modulus was caused by increased interface debonding.Combined with matrix cracking stress equation,this indicated that volume fraction decreased due to SiC matrix oxidation,resulting in degradation of proportional limit stress.Based on modified rigid body sliding model,using fiber step spacing could predict the degradation of in-plane shear strength after thermal shock,with the error between the theoretical calculation results and the actual values less than 20%.

关 键 词：2D SiC_(f)/SiC 化学气相渗透 抗热冲击行为 面剪性能 退化 

分 类 号：TB332[一般工业技术—材料科学与工程]