Enhanced High-Temperature Compression Property of TiAlNb2VW0.3 Refractory High-Entropy Alloy

In order to further enhance the high-temperature compression property of the AlNb₂TiV refractory high-entropy alloy, the AlNb₂TiVW_x (x = 0.1, 0.3, 0.5) alloys have been newly designed. The microstructure and phase composition of these alloys were investigated, and the compression property tested. The results show that white dendrite segregation can be observed in the as-cast AlNb₂TiVW_0.1 and AlNb₂TiVW_0.3 alloys, and is caused by W enrichment. W addition does not change the BCC phase composition of as-cast alloys, but the 0.3-W and 0.5-W addition can reduce the lattice constant. The AlNb₂TiVW_0.3 alloy yields the best compression property with compression strengths of 1482 MPa, 1575 MPa, and 1375 MPa at 600°C, 700°C, and 800°C, respectively. Furthermore, at 200–600°C, under an initial compression stress of 500 MPa, the stress–time curve of the AlNb₂TiVW_0.3 alloy is more stable compared with the AlNb₂TiV alloy. In the AlNb₂TiV alloy, the HCP phase forms in the BCC phase matrix during high-temperature compression, and the two phases have the orientation relationship of <110>_BCC//<10-10>_HCP and <111>_BCC//<0001>_HCP. However, the AlNb₂TiVW_0.3 alloy yields a good phase stability, which will be the reason for its good compression stability.