钛铝金属间化合物激光点火燃烧行为及机理  

Laser ignited burning behavior and mechanism of TiAl alloy

作　　者：吴明宇 弭光宝[2] 李培杰[2] 隋楠 董富礼 WU Mingyu;MI Guangbao;LI Peijie;SUI Nan;DONG Fuli(Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;National Center of Novel Materials for International Research,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国航发北京航空材料研究院先进钛合金航空科技重点实验室,北京100095 [2]清华大学新材料国际研发中心,北京100084

出　　处：《材料工程》2024年第5期1-16,共16页Journal of Materials Engineering

基　　金：国家自然科学基金“叶企孙”科学基金(U2141222);国家科技重大专项(J2019-Ⅷ-0003-0165)。

摘　　要：采用激光氧浓度实验方法结合超高温红外测温仪和高速摄像机原位观察、扫描电子显微分析和X射线衍射分析等方法,对钛铝金属间化合物(TiAl合金)的点火燃烧行为进行研究,揭示燃烧过程熔体的形成与运动规律、氧化物类型和结构特征,进而探讨燃烧机理。结果表明:TiAl合金发生起燃及持续燃烧的激光功率和氧浓度临界条件分别遵循抛物线规律和抛物线+直线规律,且显著高于近α型高温钛合金,即具有更好的阻燃性能;TiAl合金的起燃温度高于基体相熔点,起燃时基体部分熔化,导致Al元素由内氧化机制转变为外氧化机制;扩展燃烧阶段形成的氧化物由内侧到燃烧表面依次为Al_(2)O_(3),Al_(2)Ti_7O_(15),Al_(2)TiO_(5)和Al_(6)Ti_(2)O_(13)相,其中熔凝区内形成的连续网状Al_(2)O_(3)层能够阻碍熔体运动,燃烧区内形成的Ti-Al-O三元相通过降低内层Al_(2)O_(3)的分解压提升Al_(2)O_(3)保护层的稳定性,使TiAl合金具有良好的阻燃性能。The ignition and combustion behaviors of titanium aluminide(TiAl alloy) were studied by using laser oxygen concentration experimental method combined with ultra-high temperature infrared thermometer, high-speed camera in-situ observation, scanning electron microscopy and X-ray diffraction.The formation and movement laws of the molten body, types and structural characteristics during the combustion process were revealed, and the molten body mechanism was further explored. The results show that the critical conditions of laser power and oxgyen concentration for the ignition and sustained burning of TiAl alloy follow parabolic and parabolic+linear laws, respectively, which are significantly higher than those of near α high temperature titanium alloy, indicating the better flame retardant properties of TiAl alloy. The ignition temperature of TiAl alloy is higher than the melting point. During the ignition period, the partial melting of the matrix causes the transition of Al element from internal oxidation to external oxidation. The oxides formed during the sustained burning stage are characterized as Al_(2)O_(3), Al_(2)Ti_(7)O_(15), Al_(2)TiO_(5), and Al_(6)Ti_(2)O_(13) phases from the inner side to the burning surface. The continuous network Al_(2)O_(3) layer formed in the fusion zone can hinder the movement of the melt. The Ti-Al-O ternary phase formed in the combustion zone can improve the stability of the Al_(2)O_(3) protective layer by reducing the decomposition pressure of Al_(2)O_(3), thus leading to the better flame retardant performance of TiAl alloy.

关 键 词：TIAL合金 激光点火 氧化燃烧产物 燃烧机理 起燃温度 

分 类 号：TG146.2[一般工业技术—材料科学与工程]