Joining dissimilar metals for guidewire applications

Abstract

One aspect is a medical guidewire having a first wire section of a first material and a second wire section having a second material different from the first material. A joining section is adjacent both the first and second wire sections, and the joining section has a feature configured hold the first wire section to the second wire section.

1 . A medical guidewire comprising:
 a first wire section comprising a first material;   a second wire section comprising a second material different from the first material; and   a joining section adjacent both the first and second wire sections, the joining section comprising a feature configured hold the first wire section to the second wire section.   
     
     
         2 . The medical guidewire of  claim 1 , wherein the feature comprises a joint between the first and second wire sections that extends diagonally relative to the first and second sections. 
     
     
         3 . The medical guidewire of  claim 1 , wherein the feature comprises a hypotube with a first and a second end, the hypotube receiving the first wire section at the first end and the second wire section at the second end, thereby securing them together. 
     
     
         4 . The medical guidewire of  claim 3 , wherein the portion of the first and second wire sections received in the hypotube have a taper or a radial taper. 
     
     
         5 . The medical guidewire of  claim 4 , wherein the tapered portions of the first and second wire sections overlap with the hypotube. 
     
     
         6 . The medical guidewire of  claim 1 , wherein the first material comprises one of stainless steel, nickel-chromium alloy, nickel-chromium-iron alloy, and cobalt alloy and wherein the second material comprises nickel-titanium alloy. 
     
     
         7 . The medical guidewire of  claim 3 , wherein the hypotube comprises nickel-titanium alloy. 
     
     
         8 . The medical guidewire of  claim 1 , wherein the first and second wire sections are further secured together with solder, adhesive, welding, or with adhesive, such as UV cure, heat cure, or cyanoacrylate. 
     
     
         9 . The medical guidewire of  claim 1 , wherein the joining section is a hypotube that has been cold pressed on to the first and second wire sections. 
     
     
         10 . The medical guidewire of  claim 2 , wherein the joint between the first and second wire sections is diagonal or parabolic in shape. 
     
     
         11 . The medical guidewire of  claim 1 , wherein the outer diameter of the guidewire is between 0.005 and about 0.04 inches. 
     
     
         12 . A method of forming a wire comprising:
 providing a first wire section comprising a first material;   providing a second wire section comprising a second material different from the first material;   cooling a joining section that comprises a superelastic material;   inserting the first and second wire sections into the joining section;   allowing the joining section to warm such that it compresses on to both the first and second wire section thereby joining them together.   
     
     
         13 . The method of  claim 12 , wherein the first material comprising one of stainless steel, nickel-chromium alloy, nickel-chromium-iron alloy, and cobalt alloy and wherein the second material comprising nickel-titanium. 
     
     
         14 . The method of  claim 12 , wherein cooling the joining section comprises cooling to a temperature below 32° F., and wherein allowing the joining section to warm comprises warming to room temperature. 
     
     
         15 . The method of  claim 12 , wherein the joining section comprises a Nitinol alloy.