Development of Super-Heat-Resisting IrAl Intermetallic Compound with High Strength and Good Oxidation resistance.

对x在0~0.8范围内变化的多晶Ir_xNi_x金属间化合物进行了高温压缩试验。尽管Iral(x=0)在873K以下没有表现出明显的屈服，但在高于873K的温度下，Iral发生了稳定的类形变。在1037K和1473K时，Al Al合金的流动应力分别为1200 Mpa和350 Mpa，表现出负的温度依赖性。在中间温度范围内，强度随x的增加而降低。在1073K和1473K时，Al Al合金的流动应力分别为1200 Mpa和350 Mpa，表现出负的温度依赖性。此外，在高于二元NiAl的整个温度范围内，当x=0到0.8时，IR1-xNl的比强度几乎没有变化。在整个温度范围到1473K，0.2的流动应力Ir_&lt；0.2；Ni_&lt；0.8&gt；Al在整个…上显著高于二元NiAl的。在1673K温度范围内，多晶(Ni，Ir)Al的蠕变速率比多晶NiAl的蠕变速率低2个数量级。(Ni，Ir)Al内应力的增加对提高NiAl的蠕变强度有很大贡献。形变多晶(Ni，Ir)Al中的电子显微镜观察表明，存在由位错组成的位错网络，该网络具有不同的Burgers矢量。单晶(Ni，Ir)Al的蠕变变形表现出均匀变形和扭结两种不同的宏观特征。我们认为，IR的加入抑制了NiAl的易滑移系，并促进了(Ni，Ir)Al多晶中固位位错的形成和单晶(Ni，Ir)Al中的扭结现象。添加Ir可抑制NiAl的易滑移系统{011|&lt；100；>；相反，它可能促进了{001}&lt；010&gt；滑移系的形成，形成了导致(Ni，Ir)Al高内应力的固位位错和亚晶界位错网络。较少

High-temperature compression test have been conducted on polycrystalline Ir_x Ni_x Alintermetallic compounds with x varying from O to 0.8. Although IrAl(x=0)fractures without exhibiting appreciable yielding at temperatures up to 873K, a steady state-like deformation in IrAl takes place at temperatures higher than range. The IrAl alby exhibits the 0.2% flow stress of 1200MPa at 1037K and 350MPa at 1473K, having negative temperature dependence of the strength. is improved with increasing x, On the contrary the strength decreases with increasing x in the intermediate temperature range. The IrAl alby exhibits the 02% flow stress of 1200MPa at 1073K and 350MPa at 1473K having negative temperature dependence of The strength. Furthermore, the specific strength of Ir1-xNl almost dose not with x=0 to 0.8 at temperatures higher than that of binary NiAl over the entire temperature range to 1473K The 0.2 flow stress Ir_<0.2>Ni_<0.8>Al is significantly higher than that of binary NiAl over the entir … More e temperature range In 1673K Creep rates for polycrystalline (Ni, Ir)A1 are about 2 orders of magnitude lower than those for polycrystalline NiAl. The increment of internal stress of (Ni, Ir)Al contributes greatly to the improvement of creep strength for NiAl. TEM observations in deformed polycrystalline (Ni, Ir)Al show the existence of dislocation network consisting of dislocations with deferent Burgers vector. Creep deformation of single crystal (Ni, Ir)Al exhibits two macroscopically deferent , odes, such as uniform deformation and kinking. We assume that the IR addition inhibits the easy slip system for NiAl and contributes to the formation of sessile dislocation in polycrystalline(Ni, Ir)Al and the phenomenon of kinking in single crystal (Ni, Ir)Al. Ir addition may inhibit the easy slip system{011|<100>for NiAl. Instead, it may facilitate {001}<010>slip system, resulting in the formation of sessile dislocations and subgrain boundary dislocation networks responsible for the high internal stress of (Ni, Ir)Al. Less