Hardening of the surface of titanium alloys microalloyed in a high-voltage discharge, by plastic deformation, and by aging

The effect of microalloying of the surface with aluminum and oxygen in a periodic discharge in a flow of liquid (PDFL) on the hardening of surface layers of titanium alloy VT3-1 is studied. It is shown that subsequent plastic deformation of the alloyed surfaces can increase the microhardness of the surface layer by about 15%. Aging at 500°C causes additional hardening of the surfaces subjected to PDFL due to precipitation hardening in the process of the decomposition of metastable phases. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 21–24, June, 2006.     

Hardening of the Surface of Titanium Alloy in an Alternating High-Voltage Discharge in a Flow of Liquid

The effect of electric and kinematic conditions of high-voltage alternating discharges in a flow of liquid (ADFL) on the structure, phase composition, and hardness of high-strength titanium alloy VT3-1 is studied. The complex influence of ADFL and surface plastic deformation (SPD) on the hardening and quality of the surface of the alloy is investigated. The joint effect is studied with the aim of using ADFL in the process of hardening of titanium parts operating under conditions of intense friction contact and cyclic loads.__________Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 26 – 30, February, 2005.     

Improvement of the High-Temperature Thermomechanical Treatment of Rolled Bars from Titanium Alloy VT3-1

Variation of mechanical properties and structure of bars from alloy VT3-1 obtained with the use of high-temperature thermomechanical treatment (HTTMT) due to their heating and straightening in a stretcher and due to preliminary hot deformation of preforms in a helical rolling mill is described. It is shown that straightening at 550 – 700°C with an elongation of about 2% causes a certain decrease in the ultimate rupture strength and a substantial increase in the ductility and impact toughness. Preliminary rolling in a helical rolling mill affects the properties of the bars after final heat treatment in a similar manner. The suggested process is shown to raise the quality of the bars and is realizable in the production of rolled bars from alloy VT3-1 with the use of HTTMT.     

Effect of Periodic High-Voltage Discharge in a Flow of Liquid on the Surface Layers of Structural Steels and Titanium Alloys

Results of a study of the effect of electric pulse treatment with the use of high-voltage periodic discharge in a flow of water on the structure and hardness of surface layers of specimens of steels 45KhN2MFA, 30Kh3NMAF, 12Kh18N10T and titanium alloys OT4-1 and VT6 are described. It is shown that the structure and properties of the surface in the zone of the action of electric discharge change due to the rapid fusion, crystallization, and rapid hardening of microvolumes of specimens subjected to the highly concentrated energy action. The microhardness of the surface of specimens of pearlitic steels after such a treatment is higher than after volume quenching. The microhardness of the surface layers of specimens of austenitic steel 12Kh18N10T decreases. Hardening of the surface layers of titanium alloys under the action of high-voltage discharge is substantially higher than in the case of quenching, which seems to be connected with their saturation with oxygen and nitrogen from the ionized ambient. Some regular features of the influence of the conditions of periodic discharge on the structure and properties of surface layers of the studied materials are described.     

Hardening of copper and nickel alloys during pre-recrystallization annealing and softening during secondary deformation

Metal Science and Heat Treatment -