【摘要】 研究了冷轧态ＳｉＣ颗粒（ｄｐ＝１０ｕｍ）增强ＬＹ１２复合材料（ＳｉＣｐ／ＬＹ１２）的超塑性，着重探讨了变形机制。研究表明：（１）在温度Ｔ＝８０３Ｋ（比熔点高２６Ｋ）、初始应变速率∑０＝４．８×１０－４Ｓ－１时，应变速率敏感系数ｍ值为０．４９，延伸率达２４０％;（２）超塑性变形后的晶粒尺寸约为１０ｕｍ;（３）该复合材料超塑性变形的主要机制是晶界液相和基体中动态回复调节的但却受界面液相和界面扩散流释放界面应力集中速率控制的基体晶粒的晶界滑动;（４）晶界和界面上的液相对超塑性起着极其重要的作用。更多还原

【Abstract】 Superplasticity of a cold-rolled SiC particulate (d, = 10um ) reinforced Ly 12 (SiCp/LY12) composite has been investigated with a particular focus on superplastic deformation mechanisms. The following results were obtained: (l) the composite exhibits a strain rate sensitivityvalue (m) of about 0. 49 and a maximum total elongation of 240 % at an initial strain rate of 4. 8×10-4 s-1 and at 803K which is 26 K above the solid temperature of the composite; (2) the composite has a grain size of about 10pm after superplastic deformation. (3 ) the primary superplasticdeformation mechanism in the composite is grain boundary sliding accommodated by the liquidphase at grain boundaries and the dynamic recovery in matrix but controlled by the interfacialstress relaxation by the interfacial liquid phase and interfacial diffusion flow; (4 ) the liquid phasepresents at the interfaces and grain boundaries due to partial melting plays a vital role in superplasticity in the composite更多还原