摘要
采用等温压缩试验法,研究原位合成TiB2(质量分数,8%)/6351复合材料在变形温度为300～550℃和应变速率为0.001～10s-1范围内的高温变形特性。根据动态材料模型(DMM)建立TiB2/6351复合材料的加工图。采用TEM观察压缩后试样的微观组织。结果表明:加工图上的1个失稳区出现在较高应变速率(约0.631～10s-1)区域,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,在温度320～380℃、应变速率0.01～0.3162s-1区域内主要发生动态回复,功率耗散效率为17.5%～19.8%。在温度440～500℃、应变速率0.1～0.005s-1和温度500～550℃、应变速率0.1～0.001s-1范围为动态再结晶发生区域,功率耗散效率20%～25.6%。试验参数范围内,复合材料热变形的最佳工艺参数为:热加工温度为440～500℃,应变速率为0.1～0.005s-1。
The hot deformation characteristics of in-situ temperature range of 300-550 ℃ and strain rate range TiB2 （8 wt %）/6351 composites were studied by isothermal compression in the of 0.001- 10 s^-1. The processing maps were developed on the basis of dynamic material model （DMM）. The compressed material was characterized by TEM to evaluate the microstructural transformation and instability phenomena. According to the experimental results, the processing maps present one unsteady zones of high temperature deformation of TiBJ6351 composites at higher strain rate （about 0.631-10 s^-1）, the interface separated even the particle itself cracked. The main restoration mechanisms of TiB2/6351 composites during hot deformation are dynamic recovery and dynamic recrystallization. The material exhibited a domain of dynamic recovery in the temperature range of 320-380 ℃ and strain rate range of 0.01 -0.3162 s^-1 with a power dissipation efficiency about 17.5%- 19.8%. The material underwent dynamic recrystallization （DRX） in the following temperature and strain rate ranges： （1） 440-500 ℃ and 0.1-0.005 s^-1, （2） 500-550 ℃ and 0.1-0.001 s^-1, with a power dissipation efficiency about20%-25.6%. The optimum processing parameters attained by the maps in the range of this experiment were in the temperature range of 440- 500 ℃ and in the strain rate range of 0.1 -0.005 s^-1.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2009年第A01期387-392,共6页
Rare Metal Materials and Engineering
