Method of manufacturing boron-aluminium composite tubes

Abstract

Abstract A METHOD OF FORMING HIGH STRENGTH TUBES FROM COMPOSITES COMPRISING BORON FIBERS IN AN ALUMINUM MATRIX IS DISCLOSED. A FIRST METAL TUBE HAVING AN INTERNAL DIAMETER SUBSTANTIALLY EQUAL TO THE DESIRED COMPOSITE TUBE EXTERNAL DIAMETER IS PROVIDED WITH AN EVACUATION FITTING. SHEETS IN WHICH BORON FIBERS ARE UNIDIRECTIONALLY BONDED TO ALUMINUM ARE WRAPPED AROUND A SECOND, NARROWER, METAL TUBE WITH THE FIBERS PARALLEL TO THE TUBE AXIS. THE WRAPPED SECOND TUBE IS INSERTED INTO THE FIRST TUBE AND THE INTER-TUBE SPACE IS SEALED AT EACH END, AS BY WELDING. THE INTER-TUBE SPACE IS EVACUATED AND THE FITTING SEALED. THE SECOND TUBE IS SELECTED FROM TO HAVE SUBSTANTIALLY LESS WALL STRENGTH THAN THE FIRST TUBE. PREFERABLY, THIS IS ACCOMPLISHED BY USING TUBES FORMED FROM THE SAME MATERIAL, BUT WITH THE FIRST TUBE HAVING A WALL THICKNESS AT LEAST TWICE THAT OF THE SECOND TUBE. THE ASSEMBLY IS THEN PLACED IN AN AUTOCLAVE AND HEATED 5TO A TEMPERATURE OF FROM ABOUT 800 TO 1000*F. UNDER A PRESSURE OF FROM ABOUT 3000 TO 10,000 P.S.I. THIS CAUSES THE SECOND (INNER) TUBE TO EXPAND, PRESSING THE COMPOSITE LAYER AGAINST THE INNER WALL OF THE OUTER TUBE, WHILE DIFFUSION BONDING THE WRAPPED COMPOSITE INTO A SINGLE UNITARY TUBE. THE ASSEMBLY IS COOLED AND THE FIRST AND SECOND TUBES ARE REMOVED, SUCH AS BY CHEMICAL ETCHING. A HIGHLY UNIFORM HIGH STRENGTH SEAMLESS COMPOSITE TUBE RESULTS.

Inventors

• 👤 M Weisinger

Bibliographic Details