TiZr-Based Metallic Alloys: Controllable Composite Phase Structures and Related Properties

Abstract

Composite phase structure of early transition metal-based metallic alloys, including those of crystalline, quasicrystalline and amorphous phases, can be obtained in a controllable way upon direct (in-situ) cooling (solidification) of the alloy, realized either by adjusting the alloy compositions at a fixed cooling rate or by changing the cooling rates for a given alloy composition. Some embodiments are based on the addition of later transition metals, mainly of Cu with Ni or Fe with Co in early transition metal based (mainly Ti and Zr or Hf and Nb) metallic alloys. If cooling rate is on the scale of 10 3 ° C./s, a wholly amorphous structure is obtained for most of the compositions. At reduced cooling rates, composite structures with different kinds of phases can be achieved, as illustrated graphically in FIG. 1 . Nickel addition promotes the formation of quasicrystalline phases, especially for Ti-rich alloy compositions with beryllium. A critical percentage of Ni exists below which no quasicrystalline phases will be formed.

1 . A method of controlling the composite phase structures and related properties of metallic alloys comprising:
 selecting an alloy; and   controlling composite phase structures and related properties of the metallic alloy by predetermined transition metal ratio.   
     
     
         2 . A method according to  claim 1  wherein the alloy further comprises at least two early transition metals, at least one late transition metal, and beryllium. 
     
     
         3 . An alloy according to  claim 2  wherein the early transition metal includes Ti, Zr, Hf, Nb, V, and other early transition metals selected from Group IIIB and Group IVB. 
     
     
         4 . An alloy according to  claim 2  wherein the late transition metal includes Cu, Ni, Fe, Co, and other late transition metals selected from Groups VIIB, VIIIB, or IB. 
     
     
         5 . An alloy according to  claim 2  wherein the alloy is represented by the formula:
   (Ti x Zr 1−x ) a (Cu y Ni 1−y ) b Be c ,   
       wherein
 a is an atomic percentage from 50 to 70; 
 b is an atomic percentage from 10 to 30; 
 c is an atomic percentage from 10 to 30; 
 x is an atomic fraction that satisfies the relation 0.1≦x≦0.9; and 
 y is an atomic fraction that satisfies either the relation 0≦y<0.35 or 0.65<y≦1. 
 
     
     
         6 . A method according to  claim 1  wherein the controlling composite phase structures and related properties of the metallic alloy by predetermined transition metal ratio further comprises selecting the ratio of Cu to Ni where higher Cu addition at the expense of Ni results in a wider supercooled liquid region with less glass forming ability. 
     
     
         7 . A method according to  claim 6  wherein below a critical Ni percentage no quasicrystalline phase forms. 
     
     
         8 . A method according to  claim 7  wherein the critical Ni percentage varies with the relative Ti—Zr content and the critical Ni percentage decreases with increasing relative Ti content over the overall earth transition metal content. 
     
     
         9 . A method according to  claim 8  wherein increasing the content of Ti relative to Zr and increasing the content of Ni relative to Cu increases the volume fraction of quasicrystalline phases. 
     
     
         10 . An alloy according to  claim 2 , wherein said processed article is provided by at least one of the following processing methods: conventional injection casting, die casting, squeeze casting, suction casting, strip casting, and other state-of-the-art casting techniques currently employed in research labs and industries. 
     
     
         11 . An alloy according to  claim 2 , wherein said alloy is processable into, but are not limited thereto
 1) ship, submarine (e.g., watercrafts), space station and vehicle, land-craft and aircraft frames and parts,   2) building structures,   3) armor penetrators, armor penetrating projectiles or kinetic energy projectiles,   4) protection armors, armor composites, or laminate armor,   5) engineering, construction, and medical materials and tools and devices,   6) corrosion and wear-resistant coatings,   7) cell phone and personal digital assistant (PDA) casings, housings and components,   8) electronics and computer casings, housings, and components,   9) cable armor,   10) composite power shaft,   11) laminate composite: laminate with other structural alloys for aerospace, marine, and land transportation applications, and   12) actuators and other utilization that require the combination of specific properties realizable by the present invention alloys.   
     
     
         12 . An alloy according to  claim 2 , wherein said alloy provides an ideal system to study the fundamental issues related to glass transition and glass forming ability as well as phase transition between amorphous, crystalline and quasicrystalline phases. 
     
     
         13 . A method of controlling the composite phase structures and related properties of metallic alloys comprising:
 selecting an alloy;   heating an alloy above the melting point of the alloy; and   controlling composite phase structures and related properties of the metallic alloy through control of the cooling rate of the alloy.   
     
     
         14 . A method according to  claim 13  wherein the alloy comprises at least two early transition metals, at least one late transition metal, and beryllium. 
     
     
         15 . An alloy according to  claim 14  wherein the early transition metal includes Ti, Zr, Hf, Nb, V, and other early transition metals selected from Group IIIB and Group IVB. 
     
     
         16 . An alloy according to  claim 14  wherein the late transition metal includes Cu, Ni, Fe, Co, and other late transition metals selected from Groups VIIB, VIIIB, or IB. 
     
     
         17 . An alloy according to  claim 14  wherein the alloy is represented by the formula:
   (Ti x Zr 1−x ) a (Cu y Ni 1−y ) b Be c ,   
       wherein
 a is an atomic percentage from 50 to 70; 
 b is an atomic percentage from 10 to 30; 
 c is an atomic percentage from 10 to 30; 
 x is an atomic fraction that satisfies the relation 0.1≦x≦0.9; and 
 y is an atomic fraction that satisfies either the relation 0≦y<0.35 or 0.65<y≦1. 
 
     
     
         18 . A method according to  claim 13 , wherein control of the cooling rate further comprises selecting a high cooling rate for greater likelihood of forming a monolithic amorphous phase in the selected alloy. 
     
     
         19 . A method according to  claim 13 , wherein control of the cooling rate further comprises selecting a low cooling rate for forming composite structures with different kinds of phases in the selected alloy. 
     
     
         20 . A method according to  claim 19 , wherein a low cooling rate for a Ti-rich alloy results in monolithic amorphous phase, amorphous with quasicrystalline phases, or amorphous with crystalline phases with increasing levels of Cu. 
     
     
         21 . An alloy according to  claim 14 , wherein said processed article is provided by at least one of the following processing methods: conventional injection casting, die casting, squeeze casting, suction casting, strip casting, and other state-of-the-art casting techniques currently employed in research labs and industries. 
     
     
         22 . An alloy according to  claim 14 , wherein said alloy is processable into, but are not limited thereto
 1) ship, submarine (e.g., watercrafts), space station and vehicle, land-craft and aircraft frames and parts,   2) building structures,   3) armor penetrators, armor penetrating projectiles or kinetic energy projectiles,   4) protection armors, armor composites, or laminate armor,   5) engineering, construction, and medical materials and tools and devices,   6) corrosion and wear-resistant coatings,   7) cell phone and personal digital assistant (PDA) casings, housings and components,   8) electronics and computer casings, housings, and components,   9) cable armor,   10) composite power shaft,   11) laminate composite: laminate with other structural alloys for aerospace, marine, and land transportation applications, and   12) actuators and other utilization that require the combination of specific properties realizable by the present invention alloys.   
     
     
         23 . An alloy according to  claim 14 , wherein said alloy provides an ideal system to study the fundamental issues related to glass transition and glass forming ability as well as phase transition between amorphous, crystalline and quasicrystalline phases. 
     
     
         24 . An alloy according to  claim 14 , wherein said processed article is provided by at least one of the following processing methods: conventional injection casting, die casting, squeeze casting, suction casting, strip casting, and other state-of-the-art casting techniques currently employed in research labs and industries.