【摘要】 采用Gleeble-1500D热模拟试验机对原位合成TiB2(质量分数,8%)/6351复合材料在不同变形温度和不同应变速率条件下的热变形特性进行了研究,利用透射电镜(TEM)和光学显微镜分析了压缩后试样的微观组织。结果表明,材料的流变应力随变形温度的升高而降低,随应变速率的提高而增大;材料的流变行为主要表现为加工硬化、动态回复和动态再结晶;相应的显微组织特征为:位错网络、混乱的位错团和胞状结构,亚晶及等轴晶。在应变速率和变形温度均较低时,增强体颗粒周围的基体中形成高密度位错区,但随变形温度的升高而减少;在应变速率较高时,增强体颗粒和基体的界面处开裂甚至增强体颗粒本身发生破碎。更多还原

【Abstract】 The characteristics of hot compression deformation for in-situ TiB2/6351 composites have been studied in the different temperatures and strain rates using Gleeble-1500D system and the microstructures of compression samples were observed by transmission electron microscopy(TEM) and optical microscope.The results show that flow stress is affected obviously by strain rate and deformation temperature.Flow stress decreases with deformation temperature rising at constant strain rate,and increased with strain rate falling at constant deformation temperature.The flow deformation behavior mainly includes working hardening,dynamic recovery and dynamic recrystallization,and the associated microstructures represent dislocation networks and dislocation cell structures with high density dislocations,the subgrain structures and equiaxed grains.The dislocation density domain in the matrix was formed around the reinforced particles at lower deformation temperature and strain rate,and reduced with deformation temperature increasing.At higher strain rate,the interface separated even the particle itself cracked.更多还原