Methods for forming near net-shape metal parts from binderless metal powder

Abstract

Methods for forming near net-shape metal parts include transporting a binderless metal powder mixture to a die cavity with ultrasonic energy, introducing the binderless metal powder mixture into the die cavity, and compacting the binderless metal powder mixture within the die cavity with ultrasonic energy to form a green part within the die cavity. The binderless metal powder mixture includes essentially no plastic or binder, and may consist essentially of metal particles. The methods may further include separating the green part from the mold die and sintering the green part, after separating, to form a sintered near net-shape metal part.

1 . A method for forming a near net-shape metal part, the method comprising:
 transporting a binderless metal powder mixture to a die cavity with ultrasonic energy;   introducing the binderless metal powder mixture into the die cavity; and   compacting the binderless metal powder mixture within the die cavity with ultrasonic energy to form a green part within the die cavity;   wherein the binderless metal powder mixture consists essentially of metal particles.   
     
     
         2 . The method of  claim 1 , wherein the binderless metal powder mixture includes spheroidal metal particles and angular metal particles. 
     
     
         3 . The method of  claim 2 , wherein a weight percentage of the angular metal particles in the binderless metal powder mixture is greater than 10%. 
     
     
         4 . The method of  claim 2 , wherein the angular metal particles have an average effective diameter that is greater than an average effective diameter of the spheroidal metal particles. 
     
     
         5 . The method of  claim 1 , wherein the introducing includes injecting the binderless metal powder mixture into the die cavity with ultrasonic energy. 
     
     
         6 . The method of  claim 1 , wherein the binderless metal powder mixture includes titanium and wherein each of the metal particles of the binderless metal powder mixture independently consists essentially of at least one of titanium, titanium alloy, aluminium, vanadium, chromium, iron, manganese, molybdenum, nickel, niobium, palladium, ruthenium, tin, or zirconium. 
     
     
         7 . The method of  claim 1 , further comprising maintaining, during the introducing and the compacting, a temperature of the binderless metal powder mixture at less than 80° C. 
     
     
         8 . The method of  claim 1 , further comprising sintering the green part to form the near net-shape metal part. 
     
     
         9 . The method of  claim 8 , wherein the near net-shape metal part after the sintering has a density of at least 95% of a density of a bulk metal formed from the binderless metal powder mixture. 
     
     
         10 . The method of  claim 1 , wherein the die cavity is defined by a mold die that defines a sprue configured to introduce material into the die cavity and wherein the introducing includes introducing the binderless metal powder mixture through the sprue into the die cavity. 
     
     
         11 . A method for forming a sintered near net-shape metal part, the method comprising:
 transporting a binderless metal powder mixture to a die cavity of a mold die with ultrasonic energy;   introducing the binderless metal powder mixture into the die cavity;   compacting the binderless metal powder mixture within the die cavity by inducing ultrasonic vibrations in the mold die to form a green part within the die cavity;   separating the green part from the mold die; and   sintering, after the separating, the green part to form the sintered near net-shape metal part;   wherein the binderless metal powder mixture includes essentially no plastic or binder.   
     
     
         12 . The method of  claim 11 , wherein the binderless metal powder mixture includes spheroidal metal particles and angular metal particles. 
     
     
         13 . The method of  claim 12 , wherein a weight percentage of the angular metal particles in the binderless metal powder mixture is greater than 10%. 
     
     
         14 . The method of  claim 12 , wherein the angular metal particles have an average effective diameter that is greater than an average effective diameter of the spheroidal metal particles. 
     
     
         15 . The method of  claim 11 , wherein the binderless metal powder mixture has a weight fraction of titanium of at least 80% and has one or more alloying components selected from the group consisting of aluminium, vanadium, chromium, iron, manganese, molybdenum, nickel, niobium, palladium, ruthenium, tin, and zirconium. 
     
     
         16 . The method of  claim 11 , wherein the introducing and the compacting are performed to form the green part with a weight percentage of carbon of less than 5%. 
     
     
         17 . The method of  claim 11 , wherein the introducing and the compacting are performed to form the green part with a weight percentage of oxygen of less than 1%. 
     
     
         18 . The method of  claim 11 , wherein the introducing includes distributing the binderless metal powder mixture within the die cavity with ultrasonic energy. 
     
     
         19 . The method of  claim 11 , wherein the near net-shape metal part after the sintering has a volume at least 90% of a volume of the green part. 
     
     
         20 . The method of  claim 11 , wherein the mold die defines a sprue configured to introduce material into the die cavity and wherein the introducing includes introducing the binderless metal powder mixture through the sprue into the die cavity.