CAO Mingzhou
,
XIE Yingxiu
,
XU ZengjiInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang. China
金属学报(英文版)
The microstructive and compressive properties of Ti50Al48,Mn2 and Ti50Al48Cr2 alloys are studied in this paper. Existence of x-x+y transformation in TiAl alloys is confirmed by metallographic examination, the transformation temperatures of Ti5()Al48 Mn2 and Ti50Al48Cr2 are 1375 and 1373 C , respectively. After treating within x+y phase field, the microstructure of alloys consists of lamellar zones (I) and bulk rp. The volume ratio of L /rp increases with increasing solution treatment temperature. The third alloying elements of Mn and Cr distribute perferentially over x phase at solution treatment temperatures and result in that x2 and r lamellae become thicker. The yield strength of Ti50Al48Mn2 and Ti50Al48Cr2 alloys decreases and the compressibility increases with increasing rp volume fraction.
关键词:
Ti50Al48Mn2
,
null
,
null
刘建国
,
安振涛
,
张倩
,
杜仕国
,
姚凯
,
王金
材料导报
doi:10.11896/j.issn.1005-023X.2017.04.030
为评估氧化剂硝酸羟胺的热稳定性,使用标准液体铝皿于3 K/min、4 K/min、5 K/min加热速率下进行热分析.借助非等温DSC曲线的参数值,应用Kissinger法和Ozawa法求得热分解反应的表观活化能和指前因子,根据Zhang-Hu-Xie-Li公式、Hu-Yang-Liang-Xie公式、Hu-Zhao-Gao公式以及Zhao-Hu-Gao公式,计算硝酸羟胺的自加速分解温度和热爆炸临界温度,并对热分解机理函数进行了研究.设计了7条热分解反应路径,采用密度泛函理论B3LYP/6-311++G(d,p)方法对硝酸羟胺的热分解进行了动力学和热力学计算.计算结果表明,硝酸羟胺热分解的自加速分解温度TsADT=370.05 K,热爆炸临界温度Te0=388.68K,Tbp0=397.54 K,热分解最可几机理函数的微分形式为f(a) =17×(1-α)18/17.硝酸羟胺热分解各路径中,动力学优先支持路径Path 6、Path 5、Path 4和Path 1生成NO和NO2,其次是Path 2、Path 7和Path 3生成N2和N2O.温度在373 K以下时,Path 1'反应无法自发进行,硝酸羟胺无法进行自发的热分解.从热力学的角度来看,硝酸羟胺在370.05K以下储存是安全的.
关键词:
硝酸羟胺
,
热分析
,
热稳定性
,
热分解机理
,
密度泛函理论
