Prof. Elazar Gutmanas, Reactive materials — dense in situ ceramic and ontermetallic matrix composites via pressure assited thermal explosion mode of SHS

In Reactive Materials exothermic reactions between components result in pronounced evolution of energy in short period of time. In the last decade, a gradual shift to applied research has led to the development of a number of unconventional processes based on exothermic reactions that allow simultaneous synthesis and consolidation of porous combustion products. Pressure assisted thermal explosion, TE, mode of Self-Propagating High Temperature Synthesis, SHS, results in dense products in cases when the heat evolved during TE and pressure applied are sufficient for consolidation.

SHS/TE-based Reactive Forging (RF) has been developed: self-sustained reaction is ignited by rapid heat transfer from preheated press rams to the exothermic blend, and uni-axial pressure is applied. Combined with Short Distance Infiltration (SDI) approach, RF provides conditions for fabrication of interpenetrating phase in situ composites with binary (Al₂O₃, TiB₂, TiC) or ternary (MgAl₂O₄, Ti₃SiC₂, Ti₃AlC₂, Ti₂AlC), intermetallics (NiAl, TiAl.NiTi), intermetallic-ceramic and metal-ceramic composites (MgB₂-Mg, Mg₂Si-Mg, Ti/Nb-Al₂O₃, TiNi-Al₂O₃, NiAl-Al₂O₃). Compared to traditional melt infiltration, SDI has the advantage of the considerably shorter infiltration distances (μm vs. mm/cm). The RF-SDI approach has also been successful in fabrication ceramic matrix-diamond grinding wheels, ceramics nozzles, light armor tiles, sputtering targets.

Nanostructuring of powder blends results in lower ignition temperatures, T_ig, can be used for ignition of high T_ig blends and thus for fabrication of multicomponent materials. RF approach employing exothermic inserts and “chemical furnace” approach can be used for consolidation of refractory materials. Shape Charge Liners (SCL) based on Use of reactive materials and especially those with high specific weight can improve the performance of Shape Charge Liners (SCL). Simultaneous synthesis and consolidation of reaction products employing pressure assisted SHS is a “green”, cost effective and thus perspective fabrication route of structural parts.