Can New Shape Memory Alloys Become The Next Big Actuators?

Published on 09 Sep, 2015

Memory Alloy Technology Intelligence

Shape Memory Materials (SMM) are those materials that on deformation can return to its original shape and size when subjected to high temperatures beyond a critical point. There are two types of SMM –shape memory alloy (SMA) and shape memory polymer (SMP). Ni-Ti, Fe-Pt, Cu-Al-Ni, and Cu-Zn-Ti, among others, are some of the SMAs currently being researched across industries.

SMAs tick most of the checkboxes pertaining to mechanical properties in terms of those required of a suitable actuator material, such as density, stress, strain, efficiency, and operating temperatures; however, they fail to compete with piezoelectric actuators due to low bandwidth, i.e., SMAs exhibit high response time. This particular shortcoming has been a major roadblock in SMAs being accepted as a superior replacement to current actuators, which demonstrate high bandwidth and fatigue cycles.

Recently, a team of researchers claimed to have developed a Ni-Ti-Cu based SMA that can endure 10 million fatigue cycles and still regain its remembered shape. The researchers attribute this development to Ti2Cu, a Ti-Cu based chemical. And they believe that this chemical impurity has improved the phase switching process of the SMA without undergoing physical degradation over the course of cycle.

So how does this development affect various major industries?

Biomedical

Research activity in this industry has been significant over the past decade, but most research was focused on SMAs’ application in orthopedic and dental implants. With the recent development, we can expect the use of SMAs in many critical applications, such as artificial heart valves.

Aerospace

Mechanical actuators are used to operate aircraft wings; however, considering the recent developments, SMAs may prove to be a suitable replacement to these actuators, as a lightweight, economical, and durable option.

Automotive

Companies such as GM, Hyundai, and Toyota have been exploring the potential applications of SMAs. GM introduced an SMA-based hatch-vent actuator,which helped them reduce 500 grams. As SMAs can operate consistently through 10 million cycles, it could be used as a valve actuator in combustion engines. Other applications areas may include regenerative braking, auto-transmission, and so on.

In conclusion, this development does seem to be a major breakthrough for researchers in the field of SMAs. The major challenge for SMA, henceforth, would be to prove itself as a reliable alternative to existing actuators, which looks highly likely in the long run.


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