NOVEL AMORPHOUS AND NANOSTRUCTURED Nb-Zr ALLOY

Abstract

A method for preparing an alloy, including mixing elemental powders of Nb and Zr to obtain a powder mixture, and mechanical alloying to obtain an alloyed powder mixture, where the alloyed powder is more than 50% amorphous. The spark plasma sintering machine was used for the consolidation of the Nb 60 Zr 40 sample prepared by mechanical alloying. An Nb—Zr alloy composition obtained by the method, having an average crystallite size of 18 to 26 nm, hardness of 580.

1 . A method for preparing an alloy, comprising
 mixing elemental powders of Nb and Zr to obtain a powder mixture consisting of Nb and Zr, and   mechanically alloying the powder mixture consisting of Nb and Zr in a ball mill to form a mechanically alloyed powder of atomic formula Nb x Zr y , where x:y represents the atomic percentage and ranges from 40:60 to 60:40,   wherein the mechanically alloyed powder is more than 50% amorphous, as determined by X-ray diffraction.   
     
     
         2 . The method of  claim 1 , wherein the mechanical alloying of the powder mixture forms a mechanically alloyed powder comprising at least one alloy selected from the group consisting of Nb 50 Zr 50 , Nb 55 Zr 45 , and Nb 60 Zr 40 . 
     
     
         3 - 4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the alloyed powder comprises Nb 60 Zr 40 , and the mechanically alloyed powder is at least 56% amorphous, as determined by X-ray diffraction. 
     
     
         6 . The method of  claim 1 , further comprising
 sintering the alloyed powder by spark plasma sintering.   
     
     
         7 . The method of  claim 1 , wherein a rotational speed of the ball mill during mechanical alloying is from 250 to 400 rpm. 
     
     
         8 . The method of  claim 1 , wherein a rotational speed of the ball mill during mechanical alloying is about 300 rpm. 
     
     
         9 . The method of  claim 1 , wherein the mechanical alloying is performed at a temperature ranging from 20 to 35° C. 
     
     
         10 . The method of  claim 1 , wherein the powder mixture is mechanically alloyed in tungsten carbide vials with tungsten carbide balls. 
     
     
         11 . The method of  claim 10 , wherein a ball to powder weight ratio is from 8:1 to 12:1. 
     
     
         12 . The method of  claim 10 , wherein a ball to powder weight ratio is about 10:1. 
     
     
         13 . The method of  claim 1 , wherein the mechanical alloying is performed for at least 10 hours up to less than 50 hours. 
     
     
         14 . The method of  claim 13 , wherein the mechanical alloying is performed for 30 to 40 hours. 
     
     
         15 . The method of  claim 1 , wherein the mechanical alloying is carried out with tungsten carbide balls. 
     
     
         16 - 18 . (canceled) 
     
     
         19 . The method of  claim 6 , wherein the alloy prepared by spark plasma sintering has an average crystallite size of 18-26 nm. 
     
     
         20 . The method of  claim 6 , wherein the alloy prepared by spark plasma sintering has a hardness of at least 500. 
     
     
         21 . The method of  claim 1 , wherein the mechanically alloyed powder is from 50% to 60% amorphous, as determined by X-ray diffraction. 
     
     
         22 . The method of  claim 21 , wherein the mechanically alloyed powder comprises Nb 50 Zr 50 , and the alloyed powder is 60% amorphous, as determined by X-ray diffraction. 
     
     
         23 . The method of  claim 21 , wherein the mechanically alloyed powder comprises Nb 55 Zr 45  or Nb 60 Zr 40 , and the alloyed powder is 56% amorphous, as determined by X-ray diffraction.