Czeppe Tomasz, Ochin Patrick
Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 30-059 Kraków, 25 Reymonta Street, Poland.
J Microsc. 2006 Oct;224(Pt 1):18-20. doi: 10.1111/j.1365-2818.2006.01642.x.
This study concerned phase transformations observed after rapid solidification and annealing at 500, 700 and 800 degrees C in 56.3 Ni-39.9 Al-3.8 Cu-0.06 B (E1) and 59.8 Ni-36.0 Al-4.3 Cu-0.06 B (E2) alloys (composition in at.%). Injection casting led to a homogeneous structure of very small, one-phase grains (2-4 microm in size). In both alloys, the phase observed at room temperature was martensite of L1(0) structure. The process of the formation of the Ni(5)Al(3) phase by atomic reordering proceeded at 285-394 degrees C in the case of E1 alloy and 450-550 degrees C in the case of E2 alloy. Further decomposition into NiAl (beta) and Ni(3)Al (gamma') phases, the microstructure and crystallography of the phases depended on the path of transformations, proceeding in the investigated case through the transformation of martensite crystallographic variants. This preserved precise crystallographic orientation between the subsequent phases, very stable plate-like morphology and very small beta + gamma' grains after annealing at 800 degrees C.
本研究关注在56.3Ni-39.9Al-3.8Cu-0.06B（E1）和59.8Ni-36.0Al-4.3Cu-0.06B（E2）合金（原子百分比组成）中，快速凝固并在500、700和800摄氏度退火后观察到的相变。注射铸造产生了由非常小的单相晶粒（尺寸为2 - 4微米）组成的均匀结构。在这两种合金中，室温下观察到的相是L1(0)结构的马氏体。对于E1合金，通过原子重排形成Ni(5)Al(3)相的过程在285 - 394摄氏度进行，对于E2合金则在450 - 550摄氏度进行。进一步分解为NiAl（β）和Ni(3)Al（γ'）相，这些相的微观结构和晶体学取决于相变路径，在所研究的情况下，通过马氏体晶体学变体的转变进行。这在800摄氏度退火后保留了后续相之间精确的晶体学取向、非常稳定的板状形态以及非常小的β + γ'晶粒。
