Al-nb-b master alloy for grain refining

Abstract

A method of producing a master alloy for refining the grain size of a bulk alloy comprises the step of providing an Al—B alloy and adding Nb in elemental form to form an Al—Nb—B master alloy. The Al—B alloy may be prepared by providing an Al—B alloy with a higher boron content than is required and diluting it with elemental aluminium.

1 . A method of producing a master alloy for refining the grain size of a bulk alloy, comprising the step of providing an Al—B alloy and adding Nb in elemental form to form an Al—Nb—B master alloy. 
     
     
         2 . A method as claimed in  claim 1 , wherein said Al—B alloy is prepared by providing an Al—B alloy with a higher boron content than is required and diluting it with elemental aluminium. 
     
     
         3 . A method as claimed in  claim 2 , wherein the Al—B alloy with a higher boron content is Al-5B. 
     
     
         4 . A master alloy obtained by means of a method as claimed in  claim 1 . 
     
     
         5 . A method of refining the grain of a metal alloy by adding a master alloy as claimed in  claim 4 . 
     
     
         6 . A method as claimed in  claim 5 , wherein said metal alloy comprises:
 (i) an Al—Si alloy comprising at least 3% w/w silicon or   (ii) a magnesium alloy.   
     
     
         7 . A method as claimed in  claim 6 , wherein the metal alloy is an Mg—Al alloy. 
     
     
         8 . A method as claimed in  claim 6 , wherein the metal alloy is an Al—Si alloy comprising from 3 to 25 wt% silicon.