摘要
在单晶高温合金的定向凝固过程中,有时会形成条带。为此,对它的形成机制进行了研究。结果表明:条带具有明显的起始位置,一次枝晶与合金基体的一次枝晶方向平行,条带的宽度随单晶的生长过程没有变化,与小角度晶界有明显不同的特征。在单晶高温合金的凝固过程中,陶瓷型壳的表面缺陷可能是合金晶体形核的凹面靠背基底。当枝晶前方的过冷度超过晶粒形核所需要的过冷度时,合金的条带形成。用模拟试验对条带的形成机制进行了试验验证。
The sliver was sometimes formed in the directional solidification process of single crystal superalloy. Therefor its formation mechanism was investigated. The results show that the sliver has the obvious starting location. The primary dendrite arm of the sliver is parallel with that orientation of the single crystal body and the width of sliver has no change with growth process of single crystal. So the characteristic of sliver is different with that of small angle boundary. The surface defect of ceramic shell may be concave nucleation foundation of crystal in the solidification process of single crystal superalloy. When the degree of supercooling of crystal exceeds that of nucleation need, the sliver will be formed. The formation mechanism of sliver was verified with simulation test.
出处
《热加工工艺》
CSCD
北大核心
2013年第13期31-33,37,共4页
Hot Working Technology
关键词
DD6
单晶高温合金
条带
形成机制
DD6
single crystal superalloy
sliver
formation mechanism
