Systems and methods for forming a layer onto a surface of a solid substrate and products formed thereby

Abstract

A method for forming a vehicular brake rotor involving loading a shaped metal substrate with a mixture of metal alloying components and ceramic particles in a dieheating the contents of the die while applying pressure to melt at least one of the metal components of the alloying mixture whereby to densify the contents of the die and form a ceramic particle-containing metal matrix composite coating on the metallic substrate; and cooling the resulting coated product.

What is claimed is: 
     
         1 : A system for forming a layer bonded to a surface of a solid substrate, the system comprising:
 a. a die having a base and a removable top, for enclosing the substrate in a form of a hub-disc assembly and a powder mixture consisting of a powder metal and a ceramic particulate, wherein the hub-disc assembly melts at a first temperature, and wherein the metal or metal alloy component of the powder mixture is different from the metal or metal alloy forming the substrate, and consists of a metal or metal alloy which melts at a second temperature less than the first temperature;   b. a heating subsystem configured to release energy from a provided source for heating contents of the die;   c. a mechanical subsystem configured to apply a force against the die contents; and   d. a controller coupled to control the heating subsystem and the mechanical subsystem, the controller configured to enable an exothermic reaction between the surface of the substrate and the powder by heating the contents; and to enable densification of the contents by applying the force for a period that includes time before the contents have cooled to an ambient temperature.   
     
     
         2 : The system of  claim 1 , further comprising:
 a vacuum subsystem adapted to remove gas from the contents of the die via the optional vent.   
     
     
         3 : The system of  claim 1 , wherein the substrate comprises a vented hub-disc assembly. 
     
     
         4 : The system of  claim 1 , wherein the powder mixture is press consolidated and the consolidated powder mixture is placed on the substrate in the die and treated to bond the aluminum in the consolidated powder mixture directly to the substrate without an intervening layer. 
     
     
         5 : The system of  claim 1  wherein the first temperature corresponds to the melting point of an element of the group consisting of aluminum, cobalt, copper, iron, nickel, titanium, vanadium, and zinc, or of an alloy comprising one or more elements of the group consisting of aluminum, cobalt, copper, iron, nickel, titanium, vanadium, zinc, chromium, magnesium, manganese, niobium, and silicon. 
     
     
         6 : The system of  claim 1 , wherein the powder mixture consists of aluminum or an aluminum alloy, and a ceramic particulate. 
     
     
         7 : The system of  claim 1 , wherein:
 a. the hub-disc assembly comprises aluminum or an aluminum alloy, titanium or a titanium alloy, or an iron/steel alloy; and   b. the powder metal consists of aluminum or an alloy of aluminum and silicon, or aluminum, silicon and magnesium, or aluminum and titanium, or aluminum, silicon and titanium, or a prealloyed powder selected from Ti—Al and Ti—Al—Cr—Nb.   
     
     
         8 : The system of  claim 6 , wherein the ceramic particulate comprises silicon carbide. 
     
     
         9 : The system of  claim 1 , wherein from 25% to 65% of an exterior surface of the layer formed comprises ceramic particulate. 
     
     
         10 : The system of  claim 1 , wherein the layer formed has a porosity selected from the group consisting of less than 2% by volume, less than 1% by volume, and less than 0.25% by volume. 
     
     
         11 : The system of  claim 1 , wherein the layer formed and the hub-disc assembly comprise a product having a porosity selected from the group consisting of less than 2% by volume, less than 1% by volume, and less than 0.25% by volume. 
     
     
         12 : The system of  claim 1 , wherein the powder mixture of the surface layer is further characterized by one or more of the following features:
 a. the powder mixture is binder free;   b. the powder mixture consists of about 61% by weight aluminum silicon alloy, and about 39% by weight silicon carbide;   c. the powder mixture consists of about 59.5% by weight aluminum silicon alloy, about 38% by weight silicon carbide, and about 2.5% by weight titanium;   d. the powder metal comprises aluminum silicon alloy having a distribution of particle sizes defined by D10 about 5 microns, D50 about 15 microns, and D90 about  38  microns;   e. the powder mixture comprises silicon carbide having particle size from about 10 microns to 20 microns;   f. the powder metal comprises titanium having a particle size of 100 microns or less;   g. the powder metal comprises aluminum alloy 356 or aluminum alloy 432;   h. the powder metal comprises an aluminum alloy that melts at or below 600° C.;   i. the powder metal comprises aluminum with 1 wt % to 20 wt % silicon alloy;   j. the powder metal comprises aluminum with 1 wt % to 12 wt % silicon alloy; and   k. the powder mixture comprises silicon carbide particles and 95% of the silicon carbide particles have particle size below about 50 microns.   
     
     
         13 : The system of  claim 1 , wherein the hub-disc assembly consists essentially of aluminum 1100 or aluminum alloy 5052. 
     
     
         14 : The system of  claim 1 , wherein the powder mixture is spread against one or more surfaces of the substrate. 
     
     
         15 : The system of  claim 1 , wherein the powder mixture is spread against one or more surfaces of the hub-disc assembly at a thickness selected from the group consisting of from 0.001 inch to 0.25 inch, 0.60 to 0.125 inch, 0.40 to 0.080 inch, and about 0.050 inch. 
     
     
         16 : The system of  claim 1 , wherein a quantity of liquid melt is reduced by the formation of a reaction product in a solid phase. 
     
     
         17 : The system of  claim 1 , wherein 35 volume % or more of an exterior surface of the layer comprises ceramic particulate. 
     
     
         18 : The system of  claim 1 , wherein the substrate consists essentially of an aluminum alloy that melts above 580° C. 
     
     
         19 : The system of  claim 1 , wherein the powder metal comprises titanium having a particle size of about 44 microns.