Semi-finished products from shape memory alloy
Semi-finished products made of shape memory alloys (SMA) are raw material forms based on shape memory technology, which are commercially available in a basic geometric form of wires, rods, tubes and sheets.
How are shape memory alloys produced?
Shape memory alloys are produced by melting metallurgical methods such as vacuum induction melting or vacuum arc melting. Due to the tendency of titanium to oxidize, work must be carried out in an inert gas atmosphere. In addition, special precautions must be taken with regard to charging the material and preparing the raw material.
The reason for this is that the so-called phase transformation temperatures, which play a very important role for the application, depend strongly on the chemical composition. Even the slightest impurities of oxygen, carbon or other foreign elements can lead to precipitation reactions in the melting process, which in turn change the matrix composition of the material.
Several process steps in alternation are required to refine the microstructure of SMA. This involves alternating cold forming and heat treatment (intermediate annealing), and in most cases a final heat treatment for final parameter adjustment: The shaping heat treatment.
The programming of a specific shape into an SMA component is done in a forming heat treatment. In English, this process is known as „shape setting“. This is usually done using a shaping tool with a target shape in which your component is fixed before the shaping heat treatment.
Machining, such as drilling, turning or milling, can also be applied in principle to NiTi SMA. However, machining of SMA is complicated due to some of its material properties. Machining locally introduces a high heat input into the workpiece.
On the other hand, shape memory alloy (SMA) sputtering targets can be obtained, which are not used as a product, but instead used to generate thin film applications. This semi-finished product is also called passive semi-finished product.
What are the advantages of semi-finished products made from shape memory alloys?
The production of semi-finished products from shape memory alloys (SMA) can be individually adapted to the customer’s needs. If one wishes to carry out one’s own processing steps, the purchase of a semi-finished product is suitable, as this is an intermediate product in the production process, in contrast to a finished system based on shape memory alloys. In addition, SMA offers the following advantages:
– minimum weight
– simple and compact structure
– high working capacity per volume
– noiseless operation
– electromagnetic compatibility
– less of installation space required