OBSERVATION AND KINETIC-ANALYSIS OF A METASTABLE BCC PHASE IN RAPIDLY SOLIDIFIED NI-9AT-PERCENT-ZR AND NI-8AT-PERCENT-ZR-1AT-PERCENT-X ALLOYS
OBSERVATION AND KINETIC-ANALYSIS OF A METASTABLE BCC PHASE IN RAPIDLY SOLIDIFIED NI-9AT-PERCENT-ZR AND NI-8AT-PERCENT-ZR-1AT-PERCENT-X ALLOYS
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DOI：
10.1016/0921-5093(94)90425-1
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发表时间：
1994-12-20
期刊：
影响因子：
6.4
通讯作者：
GHOSH, G
中科院分区：
文献类型：
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作者：
GHOSH, G
快速凝固Ni-9at的显微组织。%Zr和%Zr-1at。发现%X （=Si， Ti或Mo）合金主要由具有b.c.c （A2）结构的微米级晶粒组成，晶格参数a = 0.280 +/- 0.005 nm。此bc相为亚稳相，加热后分解为α - ni + Ni3Zr平衡相。利用相关的热力学数据和经典的成核和晶体生长理论，从可选晶相的动力学层次来解释b.c.c相的形成。计算出Ni-9at中获得非晶相的临界冷却速率。%Zr合金约为9 × 10(7) K s(-1)，这对于熔融纺丝工艺来说太高了。
The microstructures of rapidly solidified Ni-9at.%Zr and Ni-8at.%Zr-1at.%X (=Si, Ti or Mo) alloys are found to consist predominantly of micron-sized grains having a b.c.c. (A2) structure with lattice parameter a = 0.280 +/- 0.005 nm. This b.c.c. phase is metastable and undergoes decomposition into equilibrium phases alpha-Ni + Ni3Zr upon heating. Using relevant thermodynamic data and classical nucleation and crystal growth theory, the formation of the b.c.c. phase is rationalized in terms of kinetic hierarchy of alternative crystalline phases. We find that the calculated critical cooling rate to obtain an amorphous phase in Ni-9at.%Zr alloy is about 9 x 10(7) K s(-1) which is too high for the melt-spinning process.