Abstract
A master alloy ingot of Nb-Cr based multi-element alloy has been prepared by a vacuum non-consumable arc-melting and then a vacuum consumable arc-melting. The samples are then heat treated at 1250°C/24 h, 1350°C/24 h and 1450°C/24 h, respectively. Both the arc-melted microstructure and the heat-treated microstructure are characterized by using X-ray diffractometer, optical microscope (OM) and scanning electron microscope (SEM) equipped with energy dispersive spectrum analyzer (EDS). The results show that the arc-melted microstructure was composed of Nb solid solution (Nbss) dendrites and Laves Cr2(Nb, Ti, Hf) blocks dispersed in the Nbss dendrite intervals; after heat treatments, the phase constituents of alloy are same as those in the arc-melted microstructure. However, the microstructure is refined, and the Nbss dendrites disappear and are transformed into equiaxed crystals. Furthermore, the fine and dispersed secondary Cr2(Nb, Ti, Hf) are precipitated in the Nbss matrix. With the increase of heat treatment temperature, the microstructure became finer, and the amount of Cr2(Nb, Ti, Hf) increases.
| Original language | English |
|---|---|
| Pages (from-to) | 874-877 |
| Number of pages | 4 |
| Journal | Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering |
| Volume | 37 |
| Issue number | 5 |
| State | Published - May 2008 |
Keywords
- Arc-melting
- Heat treatment
- Microstructure evolution
- Nb-Cr based multi-element alloy