Mechanism of hardening and wear resistance at high depth in metals exposed to intense-pulse-ion beams

Full text: In recent years it is possible to create a super dense collective energy excitations in electron and atomic subsystems of solids in macro-volumes by intense-pulsed-electron (IPEB) and ion (IPIB) beams. The energy densities of such excitations (∼10-104 J/cm3) are close to ones in micro-volumes: in channels of electric breakdowns and in the tracks of heavy charged particles. It causes non-linear phenomenons such as the brittle fracture of solids, exposed to IPEB. hardening at high depths of metals under IPIB irradiation and IPEB. redistribution of alloy elements in IPIB irradiated steels. The main problem is to explain these long-range effects and to propose it's mechanism. Unfortunately now only satisfactorily models of a interaction of intense pulsed laser irradiation with solids have been developed, which included thermomechanical and quantum-mechanical conceptions. A complex physical nature of phenomenon includes plasma, thermal and mechanical processes with different structure-phase transformations for a very short time of response (10-8-1 0-6 s). Since under typical regimes of IPIB irradiation the time of a heat relaxation is essentially shorter than pulse duration ( τp), then a practically instantaneous heating of a metal in a near-surface layer induces: (1) generation of thermal shock; (2) gas-dynamic plasma ablation in the irradiated layer induces a recoil impulse. Both of these factors give use to an intense compression wave. Its pressure is equal to: P=P1+P2=Γ1W1+Γ2W2, were P1, P2 are pressures, originating from a first and a second factors; W1, W2 are the corresponding densities of absorbed dose (W); Γ1 and Γ2 are the Grueneisen parameters of a solid phase and a plasma, (Γ1≅2 for iron). As it has been shown experimentally, when metals are irradiated by intense pulsed laser and electron beams of nanosecond duration, P2 has been taken into account if intensities exceeded in several orders of the magnitudes, reached in our experiments