DFT® wire is a metal-to-metal composite developed to combine the desired physical and mechanical attributes of two or more materials into a single wire or ribbon system. As a result of extreme compressive forces imparted during the processing of the dissimilar materials, the mechanical bond formed between surfaces has been found to be metallurgically sound. This feature has given rise to a number of novel applications of DFT wire, cable or ribbon.
One of the more common uses of DFT wire is found in the medical device industry where designers have integrated the strength and biocompatibility of implant grade alloys with desired properties of other materials. The composite typically uses the outer sheath to impart strength while the core material is designed to provide conductivity, radiopacity, resiliency or MRI enhancement.
DFT wire enables the unique ability to match dissimilar materials to provide a variety of properties in a single wire system. This technology can be utilized by the engineer to resolve technical issues cost effectively.
Fort Wayne Metals has the capability to create these DFT wire materials in sizes from 0.125" to 0.001" or smaller depending on the constituents.
A typical MP35N®/Silver DFT wire material (MP-DFT-Ag) may have a variety of tensile values depending upon the amount of cold work and core percentages of the individual wires. In addition, the table in Fig. 2 is presented to compare the electrical resistivity of various core percentages to that of solid MP35N wire, a common pacemaker lead material. MP35N, 316LVM and Conichrome® tubing is kept in stock for the outer sheath. Core options, in wire form, are more abundant in general inventory.
| % C W | 25% Ag | 28% Ag | 33% Ag | 41% Ag |
|---|---|---|---|---|
| 0% | 158,200 | 148,800 | 149,600 | 124,100 |
| 20% | 201,300 | 191,200 | 192,600 | 162,800 |
| 37% | 225,600 | 216,500 | 213,800 | 165,800 |
| 50% | 237,300 | 227,300 | 224,700 | 192,400 |
| 61% | 246,000 | 236,000 | 232,400 | 200,000 |
| 69% | 256,700 | 244,000 | 239,300 | 206,400 |
| 75% | 261,200 | 248,100 | 242,300 | 209,500 |
| 80% | 267,800 | 254,500 | 249,300 | 214,900 |
| 84% | 276,000 | 264,000 | 261,600 | 217,000 |
| 87% | 278,200 | 264,300 | 262,300 | 225,000 |
| 90% | 277,300 | 264,300 | 258,400 | 223,300 |
| 92% | 281,900 | 266,900 | 254,700 | 232,200 |
Typical electrical resistance of MP-DFT wire with a silver core (units ohm/ft).
| Size | 25% Ag | 28% Ag | 33% Ag | 41% Ag | Solid MP35N Wire |
|---|---|---|---|---|---|
| 0.006 | 1.07 | 0.950 | 0.843 | 0.663 | 16.5 |
| 0.004 | 2.40 | 2.14 | 1.90 | 1.64 | 37.1 |
| 0.002 | 9.60 | 8.55 | 7.59 | 6.57 | 149 |
| 0.001 | 38.4 | 34.2 | 30.3 | 26.3 | 595 |
