Atom probe analysis of grain boundaries in rapidly-solidified Ni3Al

被引：83

作者：

Horton, J. A. ^{[1
]}

Miller, M. K. ^{[1
]}

机构：

[1] Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA

来源：

ACTA METALLURGICA | 1987年 / 35卷 / 01期

关键词：

Ni,Al is an ordered intermetallic material that has good high temperature properties. The yield stress of N&Al actually increases with an increase in test temperature. However, the stoichiometric polycrystalline binary compound has poor properties in that it exhibits low ductility and fails along the grain boundaries. In 1978, Aoki and Izumi [l] reported that additions of boron to N&Al increase the ductility and modify the failure mechanism to produce a trans-granular fracture. Liu (2,3], by refining the thermo-mechanical processing, has produced room temperature ductilities of up to 50% with a completely transgranular fracture surface and has also defined the alloy composition range over which boron is effective. Good ductilities are also achieved by rapid solidification of boron-doped N&Al from the liquid Research sponsored by the Division of Materials Sciences, U.S. Department of Energy under contract DE-ACOS-8421400 with the Martin Mariette Energy Systems, Inc;

D O I：

10.1016/0001-6160(87)90221-5

中图分类号：

TF [冶金工业];

学科分类号：

0806 ;

摘要：

The distribution of boron in a rapidly solidified Ni-24 at.% Al alloy containing 0.24 at.% B was investigated by atom probe field-ion microscopy. Boron was found to segregate to both APBs and grain boundaries. Field-ion micrographs revealed that some of the APBs and most of the grain boundaries were decorated with bright spots identified by single atom analysis as boron atoms. A 0.4-1.2 nm thick boron-enriched phase was observed on most of the grain boundaries. The distribution of this phase was not uniform either along a boundary or from boundary to boundary. The degree of long-range order as measured by the atom probe was greater than 0.97. This state of order continued to the interface between the matrix and grain boundary phase.

引用

页码：133 / 141

页数：9

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