Process for preparing molybdenum alloy by ultra-high-temperature rolling

Abstract

Provided is a process for preparing a molybdenum alloy by ultra-high-temperature rolling. The molybdenum alloy is an ultra-high strength and toughness molybdenum alloy, and includes 95 wt % to 99.9 wt % of molybdenum and 0.1 wt % to 5 wt % of a nano-ceramic oxide particle. The process includes: (1) preparing an MOx—SO3H aqueous solution; (2) preparing a precursor composite powder; (3) preparing a nano-ceramic oxide-reinforced molybdenum alloy powder by reduction; and (4) preparing the ultra-high strength and toughness molybdenum alloy by pressing and sintering.

What is claimed is: 
     
         1 . A process for preparing a molybdenum alloy by ultra-high-temperature rolling, wherein the molybdenum alloy is an ultra-high strength and toughness molybdenum alloy, and comprises 95 wt % to 99.9 wt % of molybdenum and 0.1 wt % to 5 wt % of a nano-ceramic oxide particle. 
     
     
         2 . The process according to  claim 1 , comprising the following steps:
 (1) preparing an MOx—SO 3 H aqueous solution:   mixing benzenesulfonic acid and a nano-ceramic oxide particle with a particle size of 10 nm to 200 nm in water to be uniform to obtain a mixed system, and subjecting the mixed system to hydrothermal reaction to obtain the MOx—SO 3 H aqueous solution;   (2) preparing a precursor composite powder:   preparing a molybdenum salt aqueous solution with a concentration of 0.02 mol/L to 2.5 mol/L, adding the molybdenum salt aqueous solution into the MOx—SO 3 H aqueous solution to obtain a mixed solution, adjusting the mixed solution to have a pH of 5.5 to 6.5 by adding lactic acid to obtain a solution system, and subjecting the solution system to stirring, drying, and pulverizing in sequence to obtain the precursor composite powder;   (3) preparing a nano-ceramic oxide-reinforced molybdenum alloy powder by reduction:   subjecting the precursor composite powder to two-stage reduction (i.e. first-stage reduction and second-stage reduction) in hydrogen to obtain the nano-ceramic oxide-reinforced molybdenum alloy powder, with a particle size of 0.5 μm to 5 μm; and   (4) preparing the ultra-high strength and toughness molybdenum alloy by pressing and sintering:   pressing the nano-ceramic oxide-reinforced molybdenum alloy powder, and then conducting sintering in a hydrogen atmosphere to obtain a nano-ceramic oxide-reinforced molybdenum alloy with a relative density of greater than 98%, and subjecting the nano-ceramic oxide-reinforced molybdenum alloy to ultra-high-temperature rolling to obtain the ultra-high strength and toughness molybdenum alloy.   
     
     
         3 . The process according to  claim 1 , wherein the nano-ceramic oxide particle is one selected from the group consisting of zirconia, titania, alumina, hafnia, yttria, and lanthana. 
     
     
         4 . The process according to  claim 2 , wherein in step (1) the hydrothermal reaction is conducted at a temperature of 60° C. to 90° C. for 2 h to 8 h under stirring at a speed of 50 r/min to 300 r/min. 
     
     
         5 . The process according to  claim 2 , wherein in step (2) a molybdenum salt in the molybdenum salt aqueous solution is one or more selected from the group consisting of potassium molybdate, sodium molybdate, and ammonium molybdate. 
     
     
         6 . The process according to  claim 2 , wherein in step (3) the first-stage reduction is conducted at a temperature of 350° C. to 550° C. for 4 h to 9 h with a hydrogen flow rate of 15 m 3 /h to 18 m 3 /h, and the second-stage reduction is conducted at a temperature of 800° C. to 950° C. for 8 h to 12 h with a hydrogen flow rate of 18 m 3 /h to 25 m 3 /h. 
     
     
         7 . The process according to  claim 2 , wherein in step (4) the pressing is conducted in a cold isostatic press at a pressure of 150 MPa to 200 MPa for 15 min to 20 min. 
     
     
         8 . The process according to  claim 2 , wherein in step (4) the sintering is conducted in a pressureless medium-frequency furnace at a temperature of 1,700° C. to 2,000° C. for 4 h to 10 h with a hydrogen flow rate of 18 m 3 /h to 25 m 3 /h. 
     
     
         9 . The process according to  claim 2 , wherein in step (4) the ultra-high-temperature rolling is conducted at a cogging temperature of 1,500° C. to 1,700° C. by heating once in every one rolling pass with a single deformation of 30% to 50% and a total deformation of greater than 90%. 
     
     
         10 . The process according to  claim 1 , wherein the ultra-high strength and toughness molybdenum alloy remains stable in a high-temperature environment of 1,500° C., has a tensile strength of not less than 600 MPa and an elongation of not less than 50% at room temperature, and has a tensile strength of not less than 230 MPa and an elongation of not less than 30% at a high temperature of 1,200° C. 
     
     
         11 . The process according to  claim 2 , wherein the nano-ceramic oxide particle is one selected from the group consisting of zirconia, titania, alumina, hafnia, yttria, and lanthana. 
     
     
         12 . The process according to  claim 2 , wherein the ultra-high strength and toughness molybdenum alloy remains stable in a high-temperature environment of 1,500° C., has a tensile strength of not less than 600 MPa and an elongation of not less than 50% at room temperature, and has a tensile strength of not less than 230 MPa and an elongation of not less than 30% at a high temperature of 1,200° C.