SU1449289A1 - Method of diffusion welding - Google Patents

Abstract

The invention relates to pressure welding, in particular to the diffusion welding of glass and glass, through an intermediate strip of pure metals, and can be used in aircraft instrumentation. The purpose of the invention is to increase the thermal cyclic resistance of the welded joint and process intensification. A damping sublayer containing the metal of the intermediate gasket is applied onto the surfaces of the parts to be welded in any known manner. Then place the intermediate gasket. The parts heat up the sublayer to an equiquic temperature and compress until 15-35% of the vacancy porosity is formed in the sublayer. - Then the pressure is removed, the parts are cooled and subjected to them. thermocyclic CMM test m / i cl

Description

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The invention relates to pressure welding, in particular to diffusion. Noah welding glass and sitalla through an intermediate strip of pure metals, and can be used in aviation instrumentation.

The purpose of the invention is to demonstrate the thermal cyclic resistance of the welded joint and process intensification.

The method is carried out as follows.

Preliminarily, a damping sublayer containing the metal of the intermediate gasket is applied to the surfaces being welded to the parts by any known method. Then an intermediate gasket is placed, the parts are heated to an equivalent temperature of 20 sublayers and compressed until a vacancy porosity of 15-35% is formed in the sublayer. Then the pressure is removed, the parts are cooled and subjected to thermocyclic testing.

Damping sublayer, c. the composition of which includes the metal of the gasket, provides compounds with high damping properties, which increases the resistance of the welded joint to thermal cycling.

Heating the parts to the subquired subquery temperature at its deformation at the stage of accelerated creep jj leads to the fact that the welding process proceeds without deformation strengthening of the sublayer due to slippage along the grain boundaries, which leads to a decrease in the residual welding properties. Accelerated creep at an equikoksivnoy temperature leads to intensive formation and release to the surface of active centers (very long welding parameters TV,

easily determined by the curve

Icb -fe

creep under compression under conditions of a rigorous process.

Experimentally, according to a methographic analysis, it was determined that with Tgv (0.6-0.8) Tn, the drainability of diffusion compounds sharply increases to the formation of cannular porosity along the grain boundaries of the sublayer within 15-35%. This is explained by the fact that when the porosity of the sublayer is less than 15%, it behaves exactly the same way as the underlayer of solid metal, and when the porosity is more than 35%, microcracks form and develop, which lead to a dramatic change in the cross-sectional area of the welded connection and the fall of its heat resistance to the level of a solid interlayer metal

Example. KU-1 quartz glass parts were applied by any method (sputtering, chemical or galvanic deposition, etc.) to a damping underlayer of an alloy containing 60% Mn and 40% Cu with a thickness of 20-50 microns. Then placed the intermediate strip of. copper MB (thickness 50 μm) and diffusion welding were carried out according to the following mode: Тte 1173 K, 25 MPa, where Tc corresponds to the equivalent temperature of the sublayer t from 60 min.

The quality of the welded joint rp was divided by the number of cycles of heating and cooling the samples until it lost its vacuum density. Using a metographic analysis of the cross section of welded specimens, the average porosity of the sublayer was evaluated by the grain tips, which amounted to 32%. With this porosity, a sharp

interaction) on the basis of defects j, an increase in the number of thermal cycles.

lattice (vacancies and micropores), which accelerates the process of formation of the compound. With accelerated creep. In the sublayer, a vacancy porosity forms at the grain boundaries. The thermal expansion coefficient of a porous gasket is proportionally reduced with an increase in the number of pores per unit volume compared to a monolithic sublayer, which leads to a decrease in internal stresses when cooling diffusion compounds and increasing their heat resistance.

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Claims (1)

DETAILED DESCRIPTION OF THE INVENTION A method of diffusion welding of a stack with a metal, in which an intermediate gasket is softened between the welded surfaces of the parts, the welded parts are heated to the welding temperatures, compressed and carried out an isothermal holding, characterized in that, in order to increase thermal cyclic resistance bonding and intensifying the process, preliminarily apply damping to the surfaces to be welded Axis welding parameters TV,, easily determined by curves Icb -fe creep under compression in welding conditions. Experimentally, according to the metallographic analysis, it was quickly established that with Tgv (0.6-0.8) Tn, the heat resistance of diffusion compounds increases dramatically until the formation of vacancy porosity along the grain boundaries of the sublayer within 15-35%. This is due to the fact that, with a porosity of a sublayer, less than 15%, it behaves in much the same way as a sublayer of solid metal, and with a porosity of more than 35%, microcracks form and develop, which lead to a dramatic change in the cross-sectional area of the welded joint. and the fall of its heat resistance to the level of a solid interlayer metal. Example. KU-1 quartz glass parts were applied by any method (sputtering, chemical or galvanic deposition, etc.) to a damping underlayer of an alloy containing 60% Mn and 40% Cu with a thickness of 20-50 microns. Then placed an intermediate strip of. copper MB (thickness 50 μm) and carried out diffusion welding according to the mode: Тte 1173 K, 25 MPa, where Tc corresponds to the equicogenous temperature of the sublayer, t with 60 min. The quality of the welded joint was determined by the number of heating and cooling cycles of the samples until they lose their vacuum density. Using a metallographic analysis of the cross section of welded samples, the average porosity of the sublayer was estimated from the grain boundaries, which amounted to 32%. With this porosity, a sharp 0 five DETAILED DESCRIPTION OF THE INVENTION Claims: Diffusion glass welding with metal, in which an intermediate gasket is placed between the surfaces to be welded, the parts being welded are heated to the welding temperature, compressed and carried out an isothermal holding, characterized in that, in order to increase the thermal cyclic resistance of the welded joint and intensify of the process, preliminarily applied to the surfaces being welded are damped. 314492894 G.;: g „G; p ™ :: to: ™:„: wT:; l L ° - - - “. p.„ „,„ „ vedug doc, icoquez ",; G;: 1: r, d zzZG -