The effect of Al variations in the sintering behavior and creep resistance is investigated in powder‐metallurgy‐processed titanium aluminides based on the alloy TNB‐V5 (Ti‐45Al‐5Nb‐0.2B‐0.2C at%). Two compositions are prepared with Al‐contents of 43 and 47 at%, varying Al‐content by ±2 at% relative to the reference material TNB‐V5. Specimen preparation is conducted by metal injection molding using feedstock prepared with mixtures of prealloyed and elemental powders. The sinterability of alloys with addition of elemental powders decreases in comparison to the reference material, according to dilatometry experiments. However, in experiments with the sintering furnace, it is possible to obtain porosity with values of ≈10% by sintering at 1450 °C, whereas sintering at 1500 °C decreases the porosity to less than 1% in case of 43 at% and 45 at% of Al. Even though the alloy containing 47 at% Al shows higher porosity of about 7%, the creep resistance is superior to 43 at% Al, which can be attributed to a larger colony size. In tensile tests at room temperature, the effect of porosity is very detrimental leading to significantly reduced tensile strength and total elongation. Nevertheless, in compressive creep tests, the effect of porosity is secondary to colony size.

中文翻译：

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粉末冶金处理的Ti-（43-47）Al-5Nb-0.2B-0.2C的烧结和耐蠕变性

在基于TNB-V5合金（Ti-45Al-5Nb-0.2B-0.2C at％）的粉末冶金处理的钛铝化物中研究了Al变化对烧结行为和抗蠕变性的影响。制备了两种成分，铝含量分别为43和47 at％，相对于参考材料TNB-V5，Al含量变化了±2 at％。通过使用预合金粉末和元素粉末的混合物制备的原料，通过金属注射成型进行样品制备。根据膨胀试验，与参考材料相比，添加元素粉末的合金的烧结性降低。但是，在烧结炉的实验中，通过在1450°C下烧结可以获得≈10％的孔隙率，而在1500°C下烧结则在43 at％和45 at的情况下将孔隙率降低到小于1％。铝的at％即使含有47％（原子）的Al的合金显示出约7％的较高孔隙率，其抗蠕变性也优于43％（原子）的Al，这可以归因于较大的菌落尺寸。在室温下的拉伸试验中，孔隙率的影响非常有害，导致拉伸强度和总伸长率显着降低。然而，在压缩蠕变试验中，孔隙度的影响仅次于菌落的大小。