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

对x为0 ~ 0.8的多晶Ir_x Ni_x al金属间化合物进行了高温压缩试验。尽管IrAl（x=0）在高达873K的温度下没有表现出明显的屈服，但在高于该范围的温度下，IrAl会发生稳态变形。IrAl alby在1037K和1473K下分别表现出1200MPa和350MPa的0.2%流动应力，强度与温度呈负相关关系。在中温范围内，强度随x的增大而增大，而随x的增大而减小。在1073K和1473K下，IrAl alby的流变应力分别为1200MPa和350MPa，与温度呈负相关。在1473K的整个温度范围内，当x=0 ~ 0.8时，Ir1-xNl的比强度几乎不大于二元NiAl；在1673K的整个温度范围内，0.2流动应力Ir_<0.2>Ni_<0.8>Al的比强度显著高于二元NiAl。（Ni, Ir）Al的内应力的增加对NiAl的蠕变强度的提高有很大的促进作用。变形多晶（Ni, Ir）Al的透射电镜观察表明，存在由不同Burgers矢量位错组成的位错网络。单晶（Ni, Ir）Al的蠕变表现为均匀变形和扭结两种宏观上不同的蠕变模式。我们认为IR的加入抑制了NiAl的易滑移系统，并有助于形成多晶（Ni， IR）Al中的固位错和单晶（Ni， IR）Al中的扭结现象。Ir的加入对NiAl的易滑移体系{011|<100>有抑制作用。相反，它可能促进{001}<010>滑移系统，导致（Ni, Ir）Al高内应力的固位错和亚晶界位错网络的形成。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