Improvement of creep resistance in TiB particle reinforced Ti2AlNb composite particularly above 700 °C

Effect of Volume Fraction of Reinforcement on Microstructure and Mechanical Properties of In Situ (Ti, Nb)B/Ti2AlNb Composites with Tailored Three-Dimensional Network Architecture

“…), the mechanical [7,8], wear [11], fatigue [4,18] and creep [8] properties of Ti 2 AlNb alloys can be significantly improved without sacrificing or with slight degrading of other properties. Among these reinforcements, boride is the appropriate reinforcement for the Ti 2 AlNb matrix because of its exceptional physical and chemical compatibility with Ti 2 AlNb alloys [8,19]. Emura [7,8] fabricated a 6.5 wt% TiB/Ti-22Al-27Nb composite by hot isostatic pressing (HIP) and subsequent hot rolling using TiB-containing pre-alloyed powder; the fine boride (with a length of less than 5 µm and a width of less than 1 µm) in the composite exhibited an oriented alignment along the rolling direction.…”

“…Ti 2 AlNb alloys, after three decades of development, have emerged as the most promising lightweight structural material serviced at elevated temperature and are predicted to be an alternative to the high-density Inconel 718 superalloy. Although this superalloy possesses higher specific strength than nickel-based superalloys, better plasticity and processability than other Ti-Al alloys (Ti 3 Al and TiAl), and superior high-temperature mechanical properties than Ti-based alloys, it is still difficult to completely replace the Inconel 718 superalloy with the Ti 2 AlNb alloys due to insufficient strength and creep resistance at elevated temperatures [4][5][6][7][8]. Thus, improving the mechanical properties of the Ti 2 AlNb alloy becomes an urgent problem to satisfy its application in engineering.…”

“…By the strengthening effect of these stiff reinforcements (such as Ag [9], graphene [10,11], TiC [12][13][14], TiB [15][16][17], etc. ), the mechanical [7,8], wear [11], fatigue [4,18] and creep [8] properties of Ti 2 AlNb alloys can be significantly improved without sacrificing or with slight degrading of other properties. Among these reinforcements, boride is the appropriate reinforcement for the Ti 2 AlNb matrix because of its exceptional physical and chemical compatibility with Ti 2 AlNb alloys [8,19].…”

“…Among these reinforcements, boride is the appropriate reinforcement for the Ti 2 AlNb matrix because of its exceptional physical and chemical compatibility with Ti 2 AlNb alloys [8,19]. Emura [7,8] fabricated a 6.5 wt% TiB/Ti-22Al-27Nb composite by hot isostatic pressing (HIP) and subsequent hot rolling using TiB-containing pre-alloyed powder; the fine boride (with a length of less than 5 µm and a width of less than 1 µm) in the composite exhibited an oriented alignment along the rolling direction. The subsequent tensile test revealed that the composite presented an increased strength and elastic modulus along the rolling direction and the TiB addition retarded the strength degradation of the matrix at high temperatures.…”

“…Based on the above analysis, it is clear that the volume fraction of the reinforcement is indeed closely related to the microstructure and mechanical properties of the in situ boride-reinforced Ti 2 AlNb composites with the novel 3DNA. Unfortunately, the effect of the volume fraction of boride on the microstructure and mechanical properties of the composite has not been revealed since the boride contents are fixed in the previous research (typically, 6.5 wt% [7,8], 1.6 vol% [24] and 5.5 wt% [15,20]). Moreover, though having higher plasticity than the TiAl and Ti 3 Al alloys, the Ti 2 AlNb alloys are still intrinsically brittle materials, and thus, the additional amount of boride should be limited to a specified range to avoid the premature failure of the boride-reinforced Ti 2 AlNb composite.…”