US 4,871,008 AGranted

Method of making metal matrix composites

AssigneeLanxide Technology Company, LP

InventorsRatnesh K. Dwivedi, Virgil Irick, Jr.

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Abstract

An aluminum metal matrix composite comprises an aluminum metal matrix embedding a second filter, such as a ceramic second filler, and is formed by contacting, for example, a molten aluminum metal with a permeable mass of second filler within a ceramic impervious mold formed by growing a polycrystalline oxidation reaction product into a first filler. By hermetically sealing the second filler within the mold with a body of molten aluminum metal, the latter spontaneously infiltrates the mass of second filler at moderate temperatures, e.g. about 900.degree. C., without need of any other infiltration expedients. The molten mass containing the infiltrated ceramic filler is solidified to provide the metal matrix composite which may be recovered from the mold. Optionally, the solidification is carried out under bonding conditions including maintaining the solidifying material in direct contact with the ceramic mold, to provide the metal matrix composite joined to the mold, or a part thereof, as a structural component.

Claims25

Dependent claims

A method of producing a metal matrix composite, comprising:

(a) forming a substantially impervious mold by the steps comprising of:
(i) providing a permeable preform having a cavity and comprised of a first filler material;
(ii) contacting a molten parent metal with said preform and with an oxidant to react molten parent metal with said oxidant to form an oxidation reaction product within a temperature range extending from a temperature above the melting point of said parent metal to a temperature below the melting point of said oxidation reaction product;
(iii) maintaining at least a portion of said oxidation reaction product in contact with and extending between said molten parent metal and said oxidant to progressively draw molten parent metal through the oxidation reaction product towards the oxidant and into said preform so that the oxidation reaction product continues to form within said preform at the interface between said oxidant and previously formed oxidation reaction product;
(iv) continuing said oxidation reaction within said temperature range to embed at least a portion of said preform within said oxidation reaction product by growth of the oxidation reaction product to thereby provide an impervious mold with said cavity;
and
(v) removing at least a portion of excess metal from said cavity which has not reacted with said oxidant to form oxidation reaction product;
(b) emplacing a permeable mass of a second filler material within said cavity of said impervious mold, and contacting said mass of second filler with at least one molten metal selected from the group consisting of aluminum and magnesium.
(c) hermetically sealing the mold contents for a period of time sufficient to spontaneously infiltrate said mass of second filler with said at least one molten metal;
and
(d) upon completion of step (c), solidifying said at least one molten metal to provide said metal matrix composite.

8 more elements

A method of producing a metal matrix composite, comprising:

(a) forming a substantially impervious mold by the steps comprising:
(i) providing a permeable preform comprised of a first filler material, and having therein a cavity and at least one opening at an exterior surface thereof;
(ii) contacting a molten parent metal with said preform and with an oxidant to react molten parent metal with said oxidant within a temperature range extending from a temperature above the melting point of said parent metal to a temperature below the melting point of said oxidation reaction product;
(iii) maintaining at least a portion of said oxidation reaction product in contact with and extending between said molten parent metal and said oxidant to progressively draw molten parent metal through the oxidation reaction product towards the oxidant and into said preform so that the oxidation reaction product continues to form within said preform at the interface between said oxidant and previously formed oxidation reaction product;
and
(iv) continuing said oxidation reaction within said temperature range to embed at least a portion of said preform which encloses said cavity within said oxidation reaction product by growth of the oxidation reaction product to thereby provide said impervious mold having said cavity and said at least one opening;
(v) removing at least a portion of excess metal from said cavity which has not reacted with said oxidant to form oxidation reaction product;
(b) emplacing a permeable mass of a second filler material within said cavity of said impervious mold;
(c) introducing at least one molten metal selected from the group consisting of aluminum and magnesium into said at least one opening to hermetically seal said mass of second filler material within said cavity and therein contact said second filler material with said at least one molten metal for a period of time sufficient to spontaneously infiltrate said mass of second filler material with said at least one molten metal and thereby provide a molten material containing said second filler material dispersed therein;
and
(d) upon completion of step (c), solidifying said at least one molten metal to provide said metal matrix composite.

8 more elements

Dependencies are inferred from the claim text.