【摘要】 在Gleeb-1500D热模拟机上对原位合成TiB2(质量分数,8%)/6351复合材料进行热压缩实验,基于动态材料模型的Murty准则建立了复合材料的加工图。结果表明,加工图上有一个失稳区大致出现在应变速率高于0.316s-1的区域,试样在失稳区压缩后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;TiB2/6351复合材料高温变形时的主要软化机制为动态回复和动态再结晶。结合加工图和挤压工艺确定挤压温度为520℃,挤压速度为5.8mm.s-1(应变速率为0.1s-1);挤压棒材表面质量良好无裂纹等缺陷,棒材中增强体颗粒和基体界面结合良好,基体合金中存在完整的等轴晶。这表明,采用Murty准则优化的热挤压工艺参数较合理。更多还原

【Abstract】 The hot compression test of in-situ TiB2 (mass fraction,8%)/6351 composite was carried out on Gleeble-1500D system. The processing maps of the composite were developed based on Murty instability criterion of dynamic material model. The results showed that the processing maps occurred one unsteady zone during high temperature deformation of TiB2/6351 composite at strain rate of over 0.316 s-1,the interface cracked and the particle itself even crashed in the composite during compression in instability zone. The main restoration mechanisms of TiB2/6351 composite during hot deformation were dynamic recovery and dynamic recrystallization. Extrusion temperature of 520 ℃ and extrusion velocity of 5.8 mm·s-1 (strain rate 0.1 s-1) were confirmed by using the processing maps and extrusion process. The surface of extrusion bar was of good quality without cracks. The interface between the particle and matrix bold was well and fine grains existed in the matrix. It could be concluded that hot extrusion parameters optimized on the basis of Murty criterion were suitable.更多还原