The influence of alloying on the microstructure and mechanical properties of P/M Ni3Al

Studies on drilling processes of intermetallic compounds

“…Some studies tried to overcome the drawbacks of intermetallics on the marcoalloying of Ni 3 Al and Fe 3 Al with third elements such as, boron, chromium, carbon, etc. (Aoki and Izumi, 1977;Baligidad et al, 1996Baligidad et al, , 1997Shan and Lin, 1992;Wright and Knibloe, 1990;Pan et al, 1990).…”

Multistage sintering process for Ni3Al powder metallurgical products

“…In addition, the intrinsic brittleness of a polycrystalline Ni 3 Al compound at ambient temperatures has been eliminated by microalloying with boron (0.1 pct by weight). [1][2][3][4]6] These properties make it extremely attractive for aviation and structural applications at elevated temperatures. However, the superalloys used in the turbine industry have not been replaced by nickel aluminide.…”

“…This porosity is also found in many SHS materials, [17,18] as well as in the melted and as-cast ingots. [2][3][4][5][6][7] Cold working to collapse the cast pores, then healing with a subsequent annealing treatment, is the reported postcast process in several articles. [6,8] The application of a similar cold working and annealing treatment for PM products becomes an interesting subject.…”

“…[2][3][4][5][6][7] Cold working to collapse the cast pores, then healing with a subsequent annealing treatment, is the reported postcast process in several articles. [6,8] The application of a similar cold working and annealing treatment for PM products becomes an interesting subject. Therefore, a multistage sintering, with preliminary heating to initiate a reaction between the Al and Ni powders and the (first) transient liquid phase, followed by cold working to collapse and eliminate preliminary shrinkage pores, then sintering at an elevated temperature to develop another (second) transient liquid phase to heal the collapsed pores, as well as to transform the structure into final Ni 3 Al, is proposed here.…”

“…Much research on this material has been conducted on an inert gas hot isostatic press (HIP) or on a vacuum hot press (HP). [5][6][7][8][9][10][11][12] Some other approaches, known as reaction sintering, combustion synthesis, and selfpropagating high-temperature synthesis (SHS), utilize the released exothermic heat once the powder constituents are synthesized compounds. [9][10][11][12][13][14][15][16] However, many limitations on the dimensions of the starting powders and the porosity in the final products are unavoidable, in addition to the requirement of expensive HIP or HP facilities, for first two processes.…”