First you should know the temperature for shape changing, put the shape changed alloy (as you design, bend to a angel or other way) in the hot water/liquid or other meida, then observe how many percentage it recovered.

Thank you sir

Dear sir

I am workining in the area of machining of shape memory alloy. i need to evaluate the

SME property of machined surface. Please suggest me.

You can refer to our following paper. I hope it would be useful.

S.K. Vajpai, R.K. Dube, and S. Sangal: Processing and Characterization of Cu-Al-Ni Shape Memory Alloy Strips Prepared from Pre-alloyed Powder by Hot Densification Rolling of Powder Preforms; Metallurgical and Materials Transactions A, Vol. 42A, 2011, pp. 3178-3189.

You have to proceed by step. First of all you have to calculate the Af temperature (by DSC), after this you can start with increasing percentage of plastic strain (0,5% - 1,0% -1,5% - etc), after you reached the value of plastic strain you can bring the alloy at a temperature higher of Af and measure the recovery strain. When the alloy cannot recover all the plastic strain, the difference between the initial and residual strain is the maximal recovery strain of the alloy.

Thank you sir..

Dear Manajaiah,

The shape recoverability of a SMA is dependent on the maximum deformation you have imposed by thermal or stress-induced martensitic transformation. For single crystals the maximum strain associated to the transformation can be theoretically calculated, but for polycrystalline samples (eventually with some texture) this maximum strain should be measured experimentally, as well as the maximum recoverable strain. You may use the following procedure:

* You load the sample in the high temperature phase with a moderate load (that will not produce plastic deformation) for instance between 50 and 100 MPa. This load will promote the strain during the following step.

* You cool down to the complete transformation to martensite (under the previous load), measuring the strain e1. This can be done in a thermal bath.

* Now you should withdraw the load to let the sample free, measuring the elastic (or pseudoelastic recovery. Then you may measure the remaining deformation on martensitic state, re1.

* Finally you heat up to the complete reverse transformation to high temperature phase, measuring the strain recovered by simple shape memory effect.

* This way you may calculate the percentage of the recoverable strain with respect re1.

Because of the probably simultaneous plastic deformation for high imposed strains e1, the % of the recoverable strain depend on the imposed value e1, and consequently on the initial load you applied.

If you repeat the above experiment for different initial loads, up to a value for which the e1 strain do not increase more (so the maximum induced strain), you will obtain an interesting information about the % of recoverable strain as a function of the initial imposed maximum strain, which is very useful to design any further experiments on shape memory behavior.

I hope that this short explanation could become useful for your research work.

Good luck.