摘要
基于动态材料模型（DMM），建立了Ti2AlNb基合金（Ti-22Al-25Nb）在温度94012-1060℃，应变速率0．001s^-1-10s^-1范围内的加工图，并利用该图分析了合金的高温变形特性。结果发现：在温度94012～97012，应变速率0．4s^-1～10s^-1和温度970℃—1060℃，应变速率1s^-1～10s^-1范围为流动失稳区，前者范围内主要发生绝热剪切变形和45°角剪切开裂，功率耗散率达到最小值；后者区域内以局部塑性流动和纵向开裂为主，功率耗散率小于33％。热加工图的其余部分为塑性加工的“安全区”，主要发生再结晶。在温度94012～970℃，应变速率0．001s^-1-0．4s^-1范围，以α2／O相板条球化为主；在温度970℃～1030℃，应变速率0．001s^-1～1S^-1范围，功率耗散率为35％-45％，呈现连续再结晶特征。在温度1030℃～1060℃。麻蛮谏率0．001s^-1-0.1s^-1范围。功率耗散率为45％～66％。达最大值,发生连续再结晶晶粒长大。
The hot deformation characteristics of Ti-22Al-25Nb alloy have been studied in the temperature range of 940℃-1060℃ and strain rate range of 0.001 s^-1-10 s^-1 using processing maps developed on the basis of dynamic material model （DMM）. The results show that the alloy exhibits a wide instability regime due to cracking or shear band formation at a strain rate greater than 1 s^-1. At lower temperatures （940℃-970℃）, the instability is characterized by shear cracking along 45° orientation with respect to the compression axis and adiabatic shear band formation. At higher temperatures （970°-1060°）, the instability is attributed to longitudinal cracking or flow localization. The others are safe regimes characterized by recrystallization. This alloy exhibits lathy α2/O spheroidization in the temperature range of 940℃-970℃ and strain rate range of 0.001 s^-1-0.4 s^-1 with a power dissipation efficiency of about 35%. The deformation characteristics of Ti-22Al-25Nb alloy in the temperature rang of 970℃-1060℃ and strain rate range of 0.001 s^-1- s^-1 are continuous recrystallization with a power dissipation efficiency of about 35%-45%. This alloy has a peak efficiency of 45%-66% at 1030 ℃-1060℃and 0.001 s^-1-0.1 s^-1, which is attributed to the growth of continuous recrystallized grains.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第4期592-596,共5页
Rare Metal Materials and Engineering
基金
国家"十一五"科技攻关项目(JPPT-115-173)
