Functionally graded metal substrates and process for making same

A functionally-graded metal substrate comprising:

• a functional insert;
• a surrounding body;
• wherein the functional insert and the surrounding body are two different metal compositions in the x-y plane of the substrate, the functional insert having a hi,her thermal conductivity and higher coefficient of thermal expansion than the surrounding body and the surrounding body having a lower thermal conductivity and lower coefficient of thermal expansion than the functional insert;
• wherein the surrounding body surrounds the functional insert in at least two dimensions;
• wherein the functional insert extends from a top surface of the functionally-graded metal substrate to the bottom surface of the substrate;
• wherein the functional insert comprises a metal composition selected from the group consisting of copper, nickel, iron, beryllium, aluminum, silver, copper-beryllium, copper-zinc (bronze), copper-tin (brass), copper-iron, nickel-niobium, nickel-silver, nickel-copper, iron-copper, iron-copper-carbon, iron-copper-nickel, iron-chromium, iron-copper-tin, copper-nickel-titanium-aluminum, nickel-copper-titanium, copper/tungsten, copper/molybdenum, aluminum/silicon carbide, aluminum/aluminum nitride, copper/aluminum, silver/Invar.TM., copper/cubic boron nitride, copper/diamond and copper/high conductivity carbon fiber and combinations thereof;
• wherein the surrounding body comprises a metal composition selected from the group consisting of copper, nickel, iron, beryllium, aluminum, silver, copper-beryllium, copper-zinc (bronze), copper-tin (brass), 64% iron/36% nickel (Invar.TM.), 54% iron/29% nickel/17% cobalt (Kovar.TM.). copper-iron nickel-niobium, nickel-silver, nickel-copper, iron-copper, iron-copper-carbon, iron-copper-nickel, iron-chromium, iron-copper-tin, copper-nickel-titanium-aluminum, nickel-copper-titanium, copper/tungsten, copper/molybdenum, aluminum/silicon carbide, aluminum/aluminum nitride, copper/aluminum, silver/Invar.TM., copper/cubic boron nitride, copper/diamond and copper/high conductivity carbon fiber and combinations thereof;
• and,
• wherein the functionally-graded metal substrate has a density of at least about 90% of theoretical.

A functionally-graded metal substrate comprising:

• a functional insert;
• a surrounding body;
• wherein the functional insert and the surrounding body are two different metal compositions in the x-y plane of the substrate;
• wherein the functional insert has a higher thermal conductivity and higher coefficient of thermal expansion than the surrounding body, and the surrounding body has a lower thermal conductivity and lower coefficient of thermal expansion than the functional insert;
• wherein the surrounding body surrounds the functional insert in at least two dimensions;
• wherein the functional insert extends from a top surface of the functionally-graded metal substrate to the bottom surface of the substrate;
• wherein the surrounding body is a copper/tungsten MMC containing from about 5% to about 50% by weight copper, and wherein the functional insert is a copper/tungsten MMC containing from about 20% to about 80% copper;
• and,
• wherein the functional insert has a thermal conductivity that ranges from about 200 W/mK to about 400 W/mK and wherein the surrounding body has a CTE that ranges from about 5.6 ppm/.degree. C. to about 7.0 ppm/.degree. C.

A process for making a functionally-graded metal substrate comprises:

• compacting a surrounding body powder composition having a cavity therein;
• placing a functional insert powder composition into the compact of the surrounding body composition;
• sintering the compact containing functional insert powder composition and the compact containing the surrounding body powder composition simultaneously;
• and,
• infiltrating the sintered functional insert or the sintered surrounding body or both with a molten metal to form a metal substrate that has a functional insert and a surrounding body that surrounds the functional insert.

A process for making a functionally-graded metal substrate comprising:

• compacting a surrounding body powder composition having a cavity therein;
• compacting a functional insert powder composition to form a compact;
• placing the compact of the functional insert powder composition into the compact of the surrounding body composition;
• and,
• sintering the compact containing functional insert powder composition and the compact containing the surrounding body powder composition simultaneously.