SU1237352A1 - Method of pressure welding of metal single crystals - Google Patents

Description

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The invention relates to the technology of pressure welding of single-crystal metals and can be used in the electronic and aviational industry.

The purpose of the invention is to improve the quality of welding by increasing the permissible degree of deformation and intensification of the process.

The drawing shows the implementation of the proposed method.

In the single crystals to be welded 1 and 2, a crystallographic system is previously selected that provides a single slip along the planes.

H

and Q. Then, by any known method, the samples are cut so that, after their alignment, the directions of preferential slip coincide with the axis of the single crystals, and the normals N to the planes of a single slip coincide. The connected surfaces of 3 single crystals are made flat and perpendicular to their axes, and the opposite surfaces one concave, and the other convex in the form of two pairs of planes 4, 5 and 6, 7, intersecting along lines 8 and 9, passing through the axis 10 single crystals and parallel planes Q, and Q-) of unit slip, with the intersection of planes 4 and 5 forming the concave surface less than the angle of intersection of planes 6 and 7 forming the convex surface. Before joining, the welded surfaces of single crystals are activated in oxygen-free solvent vapors, and after combining, the welded single crystals are placed in the chamber of the diffusion welding unit, a vacuum is created in it, heated to the welding temperature, and deformed by compression along the axis until the convex surface is transformed into a flat one.

The implementation of the surfaces opposite to the welded, concave and convex in the form of two surfaces 5 intersecting along the lines passing through the axis of the single crystals and parallel to the plane of a single slip with different intersection angles, and the combination of the normals to the planes of a single slip provide the possibility of deformation only through dislocation slip along selected crystallographic systems, which allows

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allowable strain interval, i.e. to intensify the process due to the activation of the surfaces by the dislocations, which improves the quality

welding. The intersection of the planes that form a convex surface at a large angle: the angle than the angle of intersection of the planes that form a concave surface also contributes to the gn-genification of the process and the improvement of the quality of welding ,.

At the moment of application of the load through flat strikers to the welded samples along their axis, the acting tangents

the stresses initially exceed the critical stresses of the motion of dislocations in planes located in the central part of the crystals near their axis. After this happens

plastic deformation, acting tangential stresses increase and exceed critical stresses in adjacent slip planes and the total deformation is already carried out

by sliding adjacent planes, etc. The end of the deformation due to the movement of dislocations along the selected single slip systems occurs at the moment of transformation into the plane of the convex, opposite to the welded surface, and its further flow is provided only by the secondary slip.

Example. Single-crystal parts of technically pure (99.92) cadmium (Cd) with a hexagonal close-packed lattice were welded. The base plane (0001) and the direction of the closest package (1120) were chosen as the unit slip system. Parts dimensions are 6-6-10 mm. The crystallographic orientation of the crystals was controlled by an X-ray method using the Epigram method.

Single crystals were cut by an electric-spark method, the surfaces being welded were made flat and perpendicular to their axes, and the opposite

Hj. Is in the form of two intersecting planes along a line passing through the axis of the single crystals, perpendicular to it and parallel to the plane of unit slip. The angle of intersection of the planes that form the opposite concave concave surface of a single crystal is equal to

12.0-1-2

and the angle of intersection of the flat nets, forming the opposite welded convex surface of another single crystal, is equal to 130 + 2.

After that, the parts were degreased in CCd4 pairs and aligned along the weld planes so that the axes of the joined crystals coincide with the crystallographic direction (il20), while simultaneously matching the normals to the planes (0001),

Next, the parts were placed in the vacuum chamber of the welding unit, a 1.2–10 Pa vacuum was created in it, the parts were heated to 420 K and deformed. at a rate up to the conversion of a convex surface into a flat one.

Mechanical tests indicated high welding quality.

QI

Editor A. Ogar

Compiled by Petros n

Tehred G.Gerber Proofreader B. Butt ha

Order 3230/13 Circulation 1001Subscription

VNIIPI State Committee "1teta USSR

on dzlam inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

METHOD OF PRESSURE WELDING OF METAL SINGLE CRYSTALS, in which the crystallographic system of single slip is preliminarily selected, the directions of sliding are predominantly aligned with the axes of the crystals, and the surfaces to be welded are made flat and perpendicular to these axes, heating and deformation by compression along the axis of the single crystals are carried out, characterized in that, in order to increase welding quality by increasing the permissible degree of deformation and intensification of the process, combine the normals to the planes of a single slip In this case, the surface of one of the single crystals opposite to the one being welded is made concave, and the other is convex in the form of two planes intersecting along the lines passing through the axis of the single crystals, perpendicular to it and parallel to the plane of unit slip, and the intersection angle of the planes, forming a concave surface, less than the angle of intersection of the planes forming a convex surface, and the deformation is carried out before converting the convex surface to a flat, SU „„ 1237352