ANALYSIS OF THE LINK BETWEEN THE HEAT SOURCE AND MICROGRAPH FOR A SHAPE MEMORY ALLOYS CU-Zn-Al

Autor/autori: C. BUBULINCA (Romania), X. BALANDRAUD2,M. GREDIAC (Franta), S. STANCIU (Romania), G.A. PLAIA?U, M. ABRUDEANU (Franta)

Rezumat: In acest articol este prezentat studiul unor aliaje cu memoria formei pe baza de cupru, numite Cu-Zn-Al, care sunt supuse la tractiune mecanica ciclica. Testele de tractiune sunt executate in conditii normale de temperatura si presiune. Scopul acestui articol este de a studia caracteristicile microstructurale al unor probe din aliaj cu memoria formei Cu-Zn-Al in timpul testelor de incercari mecanice. Toate testele au loc in aceleasi conditii. In timpul testelor aliajele se afla intr-o anumita faza. Vom analiza microstructura specifica fiecarui aliaj in functie de sursa de caldura produsa in timpul testului de ciclaj mecanic. Termografia in infrarosu va fi folosita sa masoare variatia temperaturii la suprafata specimenelor in timpul testelor. O transformare de faza poate aparea in doua moduri: prin aplicarea unei tensiuni sau prin variatia temperaturii. Se determina faza initiala in care se afla aliajul prin microscopie. Variantele de martensita din aliaj sau orientarea diferita a unei variante joaca un rol important in producerea de caldura. S-a observat ca daca la nivel microstructural sunt multe variante de martensita valorile de caldura produse sunt ridicate in timpul testelor si invers.

Cuvinte cheie: aliaje cu memoria formei, microstructura martensitica, surse de caldura, teste de ciclaj, termografie in infrarosu.


Abstract: In this article it is presented a shape memory alloy study, based on copper, namely Cu-Zn-Al, which is subjected to periodic mechanical traction. Traction is performed in conditions of normal temperature and pressure. The purpose of this article it is to study microstructure characteristics for some samples of shape memory alloys Cu-Zn-Al during mechanical tests. All tests are performed in same conditions. During these tests materials are in different states. We will analyze them microstructure in function of heat sources produced by each samples during the cycling tests. Infrared thermography was used to measure the slight variations of the temperature field on the surface of the specimens. A transformation phase occurs in two ways: by applying a stress or temperature variation. Is determining initial phase of alloy by microscopically analysis. Martensitic variants or different orientation of martensite play an important role in producing of heat. It was observed at microstructually level are many variants in specimen we measure higher values of heat produced during de cycling test and opposite.

Keywords: shape memory alloys, martensitic microstructure, heat source, cycling tests, infrared thermography

 

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