摘要
快速凝固可明显细化NiAl-Cr(Mo)-0.5Hf共晶合金的组织,使合金中的富Hf相部分以Hf固溶体的形式存在,改善了Heusler相(Ni_2AlHf)和Hf固溶体的形态和分市,明显提高了合金的室温压缩性能.快凝合金热等静压或高温热处理后,合金中的Heusler相进一步向Hf固溶体转变,而且Heusler相和Hf固溶体均由原来的近连续分布转变为不连续分布;热等静压处理快凝合金中的初生NiAl相呈现粗化的趋势,而高温热处理快凝合金中的初生NiAl相有所减少.热等静压和高温热处理工艺进一步改善了快凝合金的高温压缩性能.
The NiAl-Cr（Mo） eutectic alloy has better fracture toughness and high temperature strength among NiAl alloys. Hf addition can raise the high temperature strength of NiAl-Cr（Mo） eutectic alloy further, but decreases its room temperature compressive properties obviously, which is caused by the microsegregation of Heusler phases. The NiAl Cr（Mo）-0.5Hf alloy was rapidly solidified and then hot isostatic pressed （HIP） or high temperature treated （HTT） in order to improve the structure and property of this eutectic alloy. The results reveal that rapid solidification can well refine the microstructure of eutectic alloy and keep more amount of Hf solid solution phase in the alloy. Simultaneously, the shapes and distributions of the Heusler （Ni2AlHf） phases and Hf solid solution phases are well improved. After the HIP treatment, more Heusler phases are transformed into Hf solid solution phases, and the distributions of Heusler phases and Hf solid solution phases become homogeneous, and moreover the primary NiAl phases become coarsening obviously. After HTT, the amount of primary NiAl phases decreases a little, the Heusler phases and Hf solid solution phases become finer. The rapid solidification improves the room temperature compressive properties of the alloy significantly, the HIP and HTT improve its high temperature compressive properties further.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第9期1025-1029,共5页
Acta Metallurgica Sinica
