| 摘要 |
1,269,172. Producing metal articles etc.; forging. UNITED AIRCRAFT CORP. 21 Sept., 1970 [6 Oct., 1969], No. 44803/70. Headinsg B3A and B3H. [Also in Division F1] A compressor blade is made by securing boron fibres 12 in parallel relationship to an aluminium alloy backing sheet 14, cutting the sheet into shaped plies 18 which vary in length and width, stacking the plies one above the other and then compacting the assembly in a mould to form the blade shape. The fibres 12 may have a tungsten core and be coated with silicon carbide, the fibres being secured to sheet 14 by a coating 16 of aluminium alloy applied by plasma spraying. The plies 18 are stacked on both sides of a central aluminium core 24, the smallest ply 20 being innermost and the largest 22 outermost, and are tack welded in position prior to moulding. In the latter operation the stacked plies 18 are placed between the two parts of a die 32 disposed between pressure plates 34, 36 slidable in a housing 38 heated by an induction coil 40. The die 32 is heated in a high vacuum to between about 549‹ and 566‹ C., i.e. about 25‹ C. below the melting point of the aluminium alloy and then a pressure of about 246 kg/cm.<SP>2</SP> is applied causing the alloy to flow and fill the voids between the fibres 12. Stops 44 limit the movement of the plates 34, 36 towards each other. The temperature and pressure are maintained for about 1¢ hours after which the die 32 and blade are allowed to cool while the pressure is maintained. The blade is removed from the die and any excess alloy 42 trimmed-off. If not added prior to moulding, a pair of profiled root elements (30, Figs. 8, 9, not shown) are then secured to the blade. |
