摘要
利用 ＳＥＭ和 ＴＥＭ研究了热等静压处理（ＨＩＰ）后的 ＮｉＡｌ－２８Ｃｒ－５．５Ｍｏ－０．５Ｈｆ定向凝固合金微观组织与结构．该合金主要是由ＮｉＡｌ相、Ｃｒ（Ｍｏ）相和少量聚集在相界处的Ｈｅｕｓｌｅｒ相组成．通过对该合金高温拉伸实验发现：合金的韧脆转变温度（ＢＤＴＴ）与应变速率有关，应变速率提高一个数量级，韧脆转变温度提高５０ Ｋ．断口形貌观察发现：ＢＤＴＴ以下，该合金以β相的解理和β／Ｃｒ（Ｍｏ）的相剥离形式断裂； ＢＤＴＴ以上。
The microstructure of directionally solidified NiAl-28Cr-5.5Mo-0.5Hf eutectic alloy after hot isostatic pressing was investigated by SEM and TEM. The eutectic alloy is composed of NiAl matrix, Cr(Mo) phase and a small amount Heusler phase. Tensile testing of DS NiAl alloy was performed from room temperature to 1303 K. The brittle--to--ductile transition temperature (BDTT) is dependent on strain rate, with one order of increase in strain rate resulting in a 50 K increase in transition temperature. The observation of fracture surface showed that at temperature above BDTT, the fractograph changes from NiAl cleavage and debonding along β/Cr(Mo) interface boundary to ductile in nature.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第11期1139-1143,共5页
Acta Metallurgica Sinica
基金
国家自然科学基金重大项目! 59895152
国家863计划项目! 715- 005-0030资助
关键词
韧脆转变温度
微观组织
NIAL合金
定向凝固
microstructure
NiAl/Cr(Mo
Hf) alloy
strain rate
brittle--to--ductile transition temperature(BDP
