Method for incorporating abradable material into a housing by isostatic pressing
A method of fabricating a part ( 10 ) having a housing ( 20 ) that includes an opening ( 25 ) opening out in a free surface ( 15 ) of the part ( 10 ). The method comprises the following steps: (a) closing the opening ( 25 ) with a sheath ( 30 ), the sheath having a vacuum orifice ( 31 ) and a filling orifice ( 32 ); (b) filling the housing ( 20 ) with an abradable material ( 50 ) constituted by particles by using the filling orifice ( 32 ), and evacuating the housing ( 20 ) using the vacuum orifice ( 31 ); (c) closing the orifices ( 31, 32 ) in leaktight manner; (d) deforming the sheath ( 30 ) so as to compress the abradable material ( 50 ) in the housing ( 20 ) and heating the abradable material ( 50 ) to a temperature higher than 150° C. so that the abradable material ( 50 ) becomes sintered; and (e) subsequently lowering the temperature and the pressure.
1. A fabrication method for fabricating a part comprising an abradable material, the method comprising providing a part having a housing with an opening opening out in a free surface of said part, said housing being for receiving an abradable material, and subsequently carrying out the following steps:
(a) closing said opening with a sheath, said sheath having a vacuum orifice and a filling orifice;
(b) using said filling orifice to fill said housing with an abradable material constituted by particles, and evacuating said housing using said vacuum orifice;
(c) closing said vacuum orifice and said filling orifice in leaktight manner;
(d) deforming said sheath so as to compress said abradable material in said housing, and heating said abradable material to a temperature higher than 150° C. so that the particles of said abradable material become sintered together; and
(e) subsequently lowering the temperature and the pressure to ambient temperature and ambient pressure respectively, and removing said sheath.
2. A fabrication method according to claim 1 , wherein, after step (e), the following step (f) is performed:
(f) machining the surface of said abradable material in said opening in such a manner that said surface once machined lies substantially flush with said free surface of the part.
3. A fabrication method according to claim 1 , wherein, in step (b), said housing is filled with a plurality of layers of abradable materials, each layer being different in kind from an adjacent layer.
4. A fabrication method according to claim 1 , wherein in step (d), the following steps are performed:
(k1) heating the abradable material until all points therein are at a temperature T1 higher than 150° C., while exerting isostatic compression on said sheath so that it exerts a pressure P on said sheath; and
(k2) maintaining said pressure P and said temperature T1 until all of the particles of said abradable material become sintered.
5. A fabrication method according to claim 4 , wherein said temperature T1 is higher than the temperature at which a maximum number of pores in said abradable material are resorbed.
6. A fabrication method according to claim 1 , wherein, in step (d), the following steps are performed:
(m1) heating the abradable material until all of the points therein are at a temperature T2 lying in the range 150° C. to 500° C.;
(m2) maintaining said part at said temperature T2 and placing around said sheath a rigid enclosure filled with an incompressible fluid, and then compressing the fluid in such a manner that the fluid exerts a pressure P on said sheath; and
(m3) maintaining said pressure P and heating said abradable material to a temperature T3 higher than the temperature T2 until all of the particles of said abradable material are sintered.
7. A fabrication method according to claim 6 , wherein said temperature T3 is higher than the temperature at which a maximum number of pores in said abradable material are resorbed.