Effects of B Additions on the Intragranular and Cellular Precipitations in a Cu&ndash;Be Alloy

This paper investigates the effect of Fe, Cr and B additions, in small proportions, as alloying elements in Ni3Al with the purpose to reduce its intrinsic fragility and extrinsic embrittlement and to enhance, in the same time, its mechanical properties. It represents a development of some previous research works of the authors, proving that Ni3Al-Fe-Cr-B alloys obtained by reactive synthesis (SHS) starting from Mechanically Alloyed powder mixtures have superior both room temperature tensile strength and ductility, and compression ones at temperatures up to 800 °C, than pure Ni3Al. These create premises for their using as superalloys substitutes.

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Effect of Ti and Ti+B additions on the creep properties of 1.25 Cr-0.5 Mo steels

Metallurgical Transactions A ◽

10.1007/bf02677264 ◽

1977 ◽

Vol 8 (1) ◽

pp. 57-61 ◽

Cited By ~ 6

Author(s):

R. Viswanathan

Keyword(s):

Creep Properties ◽

B Additions

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Ductility and Fracture Behavior of Single Crystalline Ni3Al with Boron Additions

MRS Proceedings ◽

10.1557/proc-133-287 ◽

1988 ◽

Vol 133 ◽

Cited By ~ 10

Author(s):

F. E. Heredia ◽

D. P. Pope

Keyword(s):

Fracture Behavior ◽

Room Temperature ◽

Constant Strain Rate ◽

Tensile Tests ◽

Strengthening Effect ◽

Single Crystalline ◽

B Additions ◽

High Temperature Tensile ◽

Tension Compression Asymmetry ◽

Positive Effect

ABSTRACTLow and high temperature tensile tests were performed on single crystals of pure Ni3Al and Ni3Al+B in order to determine the effect of B additions on the ductility and fracture behavior. Tests were carried out in air at a constant strain rate of 1.3 × 10−3 s−1. The orientations tested were [001] for which the yield stress in tension is always greater than in compression, and those for which the tension/compression asymmetry is zero ([T=C]) for each particular composition. At room temperature, the results show a positive effect of B additions on both the fracture stress and on the ductility. The ductility at 800K appears to decrease monotonically with B additions. The largest ductilities are found for [T=C] at room temperature where an improvement of about 26% (resolved strain) for an addition of 0.2 at% B was obtained. However, the most dramatic increase in ductility occurs for the [001] oriented samples at room temperature where a 55% improvement was measured over that of pure Ni3Al. Fracture surfaces show a combination of massive slip, some cleavage, and heavily dimpled areas. These observations show that B additions not only increase the ductility of polycrystalline Ni3Al, as has been previously observed by many investigators, but also that of the already-ductile single crystalline material, indicating that a “bulk effect” should be added to the grain boundary strengthening effect of B when explaining the improvement in ductility of polycrystalline Ni3Al due to B additions.

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