Advancing Nitinol from melt to medical device

Thu, 07 May 2026 12:00:00 Z

Recent advances in melting technology, particularly the addition of plasma arc melting (PAM) alongside traditional vacuum arc remelting (VAR), are producing a new generation of Nitinol with improved microstructural control. At the same time, the industry’s first collaborative, multi-company validation effort, the PRIME project, has tested these materials across the full manufacturing chain, from ingot to finished device.

For engineers, the result is clear: today’s Nitinol options are cleaner, more consistent, and supported by significantly more data than in the past.

Why inclusion control matters

One of the most important factors driving these improvements is inclusion control. Fatigue performance in Nitinol is closely tied to crack initiation, which often originates from non-metallic inclusions, such as titanium carbide or oxide particles. Reducing the size and frequency of these inclusions has a direct impact on device durability, particularly in fatigue-critical applications.

This is where newer melting methods stand out. While traditional VAR-processed material meets established ASTM standards, PAM-based processes enable tighter control over inclusion size and distribution. The result of this method at Fort Wayne Metals is Gen II Altus™ Nitinol, which contains a maximum inclusion size of 20 μm and supports the demands of neurovascular stents as well as non-medical applications such as robotic flexures and precision instrumentation.

Validated performance across the supply chain

The PRIME project (prime-ingot.com) provides real-world validation of this progress. Across five independent organizations, spanning melt, tube manufacturing, and device production, multiple generations of Nitinol materials were processed using standard workflows without modification.

The results were consistent: no manufacturing complications, strong mechanical performance, and full compliance with industry standards across multiple device types, including peripheral stents and heart valve frames.

Just as importantly, tube processing itself further reduced inclusion size, demonstrating that downstream manufacturing steps can enhance material cleanliness beyond the starting ingot. This reinforces the idea that melt quality and process control work together to drive final device performance.

What this means for device design

These advancements are not just incremental improvements. They meaningfully expand what engineers can expect from Nitinol:

Improved fatigue performance through smaller, more controlled inclusions
Seamless manufacturability using existing, validated production processes
Greater consistency across suppliers and production lots
Reduced supply chain risk with validated dual-sourcing options
Expanded design flexibility with new alloy variants and material forms

Beyond performance improvements, these advancements also address a longstanding industry concern: supply chain risk. With validated material produced through both VAR and PAM processes, device manufacturers now have viable dual-sourcing options without compromising quality. This added flexibility reduces dependence on a limited number of suppliers and improves overall resilience.

Expanding on what Nitinol can do

Control over the melt process is also unlocking new material possibilities. With greater flexibility in composition and processing, specialized Nitinol variants are emerging to solve specific design challenges, from increased stiffness and pushability to improved radiopacity and reduced friction. These options allow engineers to move beyond standard superelastic behavior and tailor materials more precisely to application needs.

Looking ahead, continued testing, particularly in fatigue performance at the device level, will further quantify the benefits of these advancements. Early results already show equal or improved performance compared to existing materials, reinforcing confidence in next-generation Nitinol.

Taken together, these developments mark a meaningful step forward. Cleaner material, broader supply, and expanded design options are giving engineers more control and more confidence—ultimately creating new opportunities to push the performance of medical devices even further.

CoNiCr-Nitinol composite wires for guidewire applications

Mon, 17 Feb 2020 12:00:00 Z

Fort Wayne Metals developed a CoNiCr-Nitinol composite wire targeted for use in advanced guidewire applications. This novel material combines the strength and stiffness of CoNiCr alloys with the superelasticity of Nitinol, offering a seamless transition from proximal stiffness to distal flexibility. These properties may enhance physician control, improve tip performance, and facilitate the crossing of chronic total occlusions (CTOs) without requiring a jointed core wire.

Material composition and manufacturingThe composite wire consists of:

Outer Shell: 35N LT® (CoNiCrMo alloy) for high strength and stiffness
Core: Ni50.8Ti49.2 Nitinol for superelasticity and kink resistance

Manufactured using DFT® technology, the wire undergoes co-processing, cold reduction, and heat treatments. This process combines two dissimilar materials into a single wire system, achieving optimal strength, flexibility, and superelastic performance.

Key performance characteristics

Mechanical strength and flexibility

The CoNiCr shell provides an initial elastic modulus of 197 GPa and an ultimate tensile strength of 2600 MPa.
The Nitinol core maintains an elastic modulus of 48 GPa with an ultimate tensile strength of 1170 MPa.
The wire demonstrates a seamless transition from stiffness to flexibility, allowing for precise control.

Torque control and one-to-one response

Rotational testing confirmed minimal lag between proximal and distal ends, providing sufficient torque transmission.
Optical tracking in a whip test showed that the wire exceeded ASTM F2819 standards for straightness.

Bending and kink resistance

The composite wire maintains higher bending stiffness in the proximal section for pushability.
The Nitinol core offers lower bending resistance in the distal end, improving navigation and kink resistance.

Joint-free design

Unlike traditional guidewires that require soldering or adhesives to join different materials, this composite wire integrates high strength and superelasticity into a single, continuous structure.
This composite wire product has the potential to reduce failure points and enhance reliability.

Fort Wayne Metals - Technical Blog

Advancing Nitinol from melt to medical device

CoNiCr-Nitinol composite wires for guidewire applications