Premium
Sintering and Creep Resistance of Powder‐Metallurgy‐Processed Ti‐(43‐47)Al‐5Nb‐0.2B‐0.2C
Author(s) -
Soyama Juliano,
Limberg Wolfgang,
Ebel Thomas,
Pyczak Florian
Publication year - 2020
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.202000377
Subject(s) - materials science , sintering , porosity , powder metallurgy , creep , ultimate tensile strength , metallurgy , alloy , metal injection molding , titanium , molding (decorative) , composite material
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.