Microstructure evolution and reaction behavior of Cu–Ni alloy and B_4C powder system

Microstructure evolution and reaction behavior of Cu–Ni alloy and B_4C power system was studied by in-situ and static experimental investigations along with theoretical calculations. The reaction process was as follows. Firstly,B_4C decomposed into B and C atoms, and then B atoms diffused into Cu–Ni matrix, leading to the formation of Ni_2B particles. Subsequently, Ni atoms diffused into B_4C, forming a loose mixture of Ni_2B and amorphous C at the initial powder boundary. Finally, with the completion of reaction, Ni_2B particles at the powder boundary grew into a monolithic block, and then C substance was excluded out and accumulated at the edge of this monolithic Ni_2B block. It is believed that the formation of Ni_2B phase is caused by the most negative change of Gibbs free energy among all the potential reactions between Ni–B and Ni–B_4C systems.

Microstructure evolution and reaction behavior of Cu–Ni alloy and B4C powder system

Microstructure evolution and reaction behavior of Cu–Ni alloy and B₄C power system was studied by in-situ and static experimental investigations along with theoretical calculations. The reaction process was as follows. Firstly, B₄C decomposed into B and C atoms, and then B atoms diffused into Cu–Ni matrix, leading to the formation of Ni₂B particles. Subsequently, Ni atoms diffused into B₄C, forming a loose mixture of Ni₂B and amorphous C at the initial powder boundary. Finally, with the completion of reaction, Ni₂B particles at the powder boundary grew into a monolithic block, and then C substance was excluded out and accumulated at the edge of this monolithic Ni₂B block. It is believed that the formation of Ni₂B phase is caused by the most negative change of Gibbs free energy among all the potential reactions between Ni–B and Ni–B₄C systems.