Metallic glass composites with controllable work-hardening capacity

Abstract

There are provided metallic glass matrix composites with controllable work-hardening capacity. In more detail, there are provided metallic glass matrix composite with controllable work-hardening capacity capable of having significantly excellent toughness due to a metastable second phase precipitated in-situ in a metallic glass matrix by polymorphic phase transformation during a solidification process without a separate synthetic process, and capable of controlling work-hardening capacity by measuring physical properties of a second phase and adjusting a volume fraction (V f ) of the second phase due to constant correlation between the physical properties (absorbed energy E t a , a phase transformation temperature T Ms , or a hardness H 2nd ) of a metastable B2 second phase precipated in the metallic glass matrix and the absorbed energy (E p a,V ) by work-hardening per unit volume fraction of the second phase in the metallic glass matrix.

What is claimed is: 
     
         1 . A metallic glass composite with controllable work-hardening capacity, the metallic glass composite comprising:
 a metallic glass matrix; and   a phase-transformable metastable B2 second phase precipitated in the metallic glass matrix by polymorphic phase transformation   wherein the work-hardening capacity is controlled by absorbed energy (E t   a ), a phase transformation temperature (T Ms ), or hardness (H 2nd ) and phase lo volume fraction (V f ), which are physical properties of the phase-transformable metastable B2 second phase.   
     
     
         2 . The metallic glass composite of  claim 1 , wherein:
 the metallic glass matrix comprises about 35 at % to about 58 at % of Ti, about 35 at % to about 50 at % of Cu, about 4.5 at % to about 12 at % of Ni, and about 0.5 at % to about 5 at % of Si.   
     
     
         3 . The metallic glass composite of  claim 2 , wherein:
 the metallic glass matrix further comprises one or more elements selected from Zr, Hf, V, Nb, Ta, Nb, and Cr, which are early transition metals (ETM), and Al and Sn, which are post transition metals (PTM), in a range of about 1 at % to about 15 at %.   
     
     
         4 . The metallic glass composite of  claim 1 , wherein:
 absorbed energy (E p   a,V ) by work-hardening per unit volume fraction of a phase-transformable metastable B2 second phase in the metallic glass matrix and absorbed energy (E t   a ) of the phase-transformable metastable B2 seocnd phase satisfy the following Equation:
     E   p   a,V   =A   0   E   t   a   −B   0    
   (A 0 =about 5(±0.5)/10 3 , B 0 =about 6(±3)/10 2 )   (A 0 =about 5(±0.5)/10 3 , B 0 =about 6(±3)/10 2 )   unit: E p   a,V (J/cm 3 vol %), E t   a (J/cm 3 ).   
     
     
         5 . The metallic glass composite of  claim 1 , wherein:
 absorbed energy (E p   a,V ) by work-hardening per unit volume fraction of a phase-transformable metastable B2 second phase in the metallic glass matrix and a martensite-start temperature (T Ms ) of the phase-transformable metasatblae B2 second phase satisfy the following Equation:
     E   p   a,V   =C   0   T   Ms   −D   0    
   (C 0 =about 2.6(±0.2)/10 3 , D 0 =about 1.6(±0.2)/10)   unit: E p   a,V (J/cm 3 vol %), T Ms (K).   
     
     
         6 . The metallic glass composite of  claim 1 , wherein:
 absorbed energy (E p   a,V ) by work-hardening per unit volume fraction of a phase-transformable metastable B2 second phase in the metallic glass matrix and a hardness value (H 2nd ) of the phase-transformable metastable B2 second phase satisfy the following Equation:
     E   p   a,V   =E   0   H   2nd   +F   0    
   (E 0 =about −5(±0.5)/10 3 , F 0 =about 2.7(±0.5)   unit: E p   a,V (J/cm 3 vol %), H 2nd (HV).   
     
     
         7 . The metallic glass composite of  claim 1 , wherein:
 a hardness value (H 2nd ) of the phase-transformable metastable B2 second phase and a martensite-start temeprature (T Ms ) thereof satisfy the following Equation:
     H   2nd =about 469.6±10'0.33±0.1 T   Ms  
 
   unit: H 2nd (HV), T Ms (K).   
     
     
         8 . The metallic glass composite of  claim 1 , wherein:
 controlling of a volume fraction of the phase-transformable metastable B2 second phase in the metallic glass matrix is performed through a suction casting process.   
     
     
         9 . The metallic glass composite of  claim 8 , wherein:
 the metallic glass composite is formed by casting using arc plasma having output power of about 5 V to about 50 V (output voltage) and about 30 A to about 300 A (output current).   
     
     
         10 . The metallic glass composite of  claim 8 , wherein:
 the metallic glass composite is formed by introducing a molten metal into a mold by a pressure of about 0 torr to about 600 torr and casting the molten metal.   
     
     
         11 . The metallic glass composite of  claim 8 , wherein:
 the metallic glass composite is formed by casting the injected molten metal while adjusting cooling capacity in a range of about 10 1  K/s to about 10 4  K/s.