Hf–Ta based alloys have recently been investigated as potential candidates for high-temperature structural applications. While most attentions have been given to the properties above ~1200 °C where the alloys are mainly single-phase BCC structures and have excellent oxidation performance due to formation of super-oxides, structural properties at lower temperatures are equally important for applications in which an alloy may experience a range of temperatures. In the present work, microstructure, phase composition, mechanical properties and oxidation behavior of six Hf-25Ta-5Me alloys (Me is Mo (HTM alloy), W (HTW), 0.5Mo + 0.5 W (HTMW), Cr (HTC) or Zr (HTZ), the compositions are in at.%) are reported at temperatures below the eutectoid transformation. The alloys were prepared by arc melting followed by hot isostatic pressing for 3 h at 1400 °C and 207 MPa. All the alloys display coarse grains of partially or fully transformed (by a eutectoid reaction) high-temperature BCC phase. The eutectoid regions consist of fine lamellae of Hf-rich HCP and Ta-rich BCC phases. The ternary alloys containing W or Cr also contained small amounts of a cubic Laves phase. At 25 °C, the HTW alloy was the strongest (yield stress σ_y = 1966 MPa) but brittle and HTZ was the weakest (σ_y = 1120 MPa) but ductile among the studied alloys. Other alloys showed intermediate behaviors. In general, the room temperature ductility of the alloys increased with decreasing σ_y. All alloys maintained high strength up to 800 °C, but displayed a noticeable strength decrease at 1000 °C. At 1000 °C, HTMW was the strongest alloy (σ_y = 468 MPa) and HTC was the weakest alloy (σ_y = 368 MPa). All alloys had excellent deformability at 1000 °C. Oxidation behavior of the alloys was studied at 800 °C and 1000 °C and compared with that of Hf–27Ta binary alloy. Although the ternary additions improved oxidation resistance, overall oxidation performance of the studied alloys at 800 °C and 1000 °C was poor.

最近研究了 Hf-Ta 基合金作为高温结构应用的潜在候选者。虽然大多数注意力都集中在~1200 °C 以上合金主要是单相 BCC 结构并且由于形成超氧化物而具有优异的氧化性能的性能，但在较低温度下的结构性能对于以下应用同样重要合金可能会经历一定范围的温度。在目前的工作中，六种 Hf-25Ta-5Me 合金（Me 是 Mo（HTM 合金）、W (HTW)、0.5Mo + 0.5 W (HTMW)、Cr (HTC)）的显微组织、相组成、力学性能和氧化行为或 Zr (HTZ)，组成单位为 at.%) 在低于共析转变的温度下报告。合金通过电弧熔化制备，然后在 1400 °C 和 207 MPa 下热等静压 3 小时。所有合金都显示出部分或完全转变（通过共析反应）的高温 BCC 相的粗晶粒。共析区域由富含 Hf 的 HCP 和富含 Ta 的 BCC 相的细薄片组成。含有 W 或 Cr 的三元合金还含有少量的立方 Laves 相。在 25 °C 时，HTW 合金最强（屈服应力 σ_y  = 1966 MPa) 但脆性和 HTZ 是最弱的 (σ _y  = 1120 MPa) 但在所研究的合金中具有延展性。其他合金表现出中等行为。一般来说，合金的室温延展性随着σ _y的减小而增加。所有合金在高达 800 °C 时仍保持高强度，但在 1000 °C 时强度显着下降。在 1000 °C 时，HTMW 是最强的合金 (σ _y  = 468 MPa)，而 HTC 是最弱的合金 (σ _y = 368 兆帕）。所有合金在 1000 °C 下均具有出色的变形能力。研究了合金在 800 °C 和 1000 °C 下的氧化行为，并与 Hf-27Ta 二元合金的氧化行为进行了比较。尽管三元添加剂提高了抗氧化性，但所研究合金在 800 °C 和 1000 °C 下的整体氧化性能很差。