Dual Phase High Entropy Boride-Carbide Composites for Extreme Environments

A method of making a dual phase high entropy boride-carbide composite for extreme environments, comprising the steps of:

• utilizing a pressureless reactive sintering process;
• providing a Zr—Hf—Ti—V—B4C powder blend;
• maintaining a low sintering temperature;
• allowing the Zr—Hf—Ti—V—B4C powder blend to result in HE-Alloy powder and B4C;
• allowing the B4C to result in 4B and C and heat;
• reacting the HE-Alloy powder with the B and the C;
• and
• forming a HE-boride composite and a HE-carbide composite;
• wherein the HE-boride composite and HE-carbide composite comprise (Zr—Hf—Ti—V)B2+(Zr—Hf—Ti—V)C.

A method of making a dual phase high entropy boride-carbide composite for extreme environments, comprising the steps of:

• providing an initial mixture of B4C, Zr, Hf, Ti and V powders;
• wherein the ratio of Zr, Hf, Ti, V and B4C are in the ratio of 4:2:2:1:2;
• performing high energy ball milling using a SPEX 8000M Mixer/Mill;
• making green compacts under pressure;
• transferring the green compacts to a box furnace for pressureless sintering;
• heating the box furnace to 1500° C. under a dynamic Ar atmosphere;
• maintaining 1500° C. under the dynamic Ar atmosphere;
• transforming the green compacts to high entropy powder;
• decomposing the B4C to in an exothermic reaction to release B and C;
• reacting the high entropy powder with the B and the C;
• and
• forming a dual phase high entropy boride-carbide composite.

A dual phase high entropy boride-carbide composite for extreme environments, comprising:

• dual phases of high entropy boride (HEB) and high entropy carbide (HEC);
• wherein the high entropy boride comprises (A-X—Y—Z-D-E)B2 where A, X, Y, Z, and D have a range between 0.2 to 0.4 and E has a range between 0 and 0.4, and A, X, Y, Z, and D are from the periodic table refractory transition metal groups IVB through VIB comprising Ti, Zr, Hf, Rf, V, Nb, Ta, Cr, Mo, W;
• and
• wherein the high entropy carbide comprises (A-X—Y—Z-D-E)C where A, X, Y, Z, and D have a range between 0.2 to 0.4 and E has a range between 0 and 0.4, and A, X, Y, Z, and D are from the periodic table refractory transition metal groups IVB through VIB comprising Ti, Zr, Hf, Rf, V, Nb, Ta, Cr, Mo, W.