The Effect of Subsequent Stress-Induced Martensite Aging on the Viscoelastic Properties of Aged NiTiHf Polycrystals

Anton I Tagiltsev,Ekaterina S Marchenko,Ekaterina E Timofeeva,Yuriy I Chumlyakov,Elena Y Panchenko,Ibrahim Karaman

doi:10.3390/met11121890

Anton I Tagiltsev, Ekaterina S Marchenko + Show 4 more

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https://doi.org/10.3390/met11121890

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Abstract

This study investigated the effect of stress-induced martensite aging under tensile and compressive stresses on the functional and viscoelastic properties in Ni50.3Ti32.2Hf17.5 polycrystals containing dispersed H-phase particles up to 70 nm in size obtained by preliminary austenite aging at 873 K for 3 h. It was found that stress-induced martensite aging at 428 K for 12 h results in the appearance of a two-way shape memory effect of −0.5% in compression and +1.8% in tension. Moreover, a significant change in viscoelastic properties can be observed: an increase in internal friction (by 25%) and a change in elastic modulus in tensile samples. The increase in internal friction during martensitic transformation after stress-induced martensite aging is associated with the oriented growth of thermal-induced martensite. After stress-induced martensite aging, the elastic modulus of martensite (EM) increased by 8 GPa, and the elastic modulus of austenite (EA) decreased by 8 GPa. It was shown that stress-induced martensite aging strongly affects the functional and viscoelastic properties of material and can be used to control them.

Highlights

NiTi-based shape memory alloys (SMAs) have attracted much scientific attention in recent decades
The other feature of martensitic transformations (MTs) observed is a temperature peak of internal friction (Mp and Ap in Table 1), which does not shift with a change in frequency (Figure 2)
The SIM-aging resulted in a change in elastic modulus (EM increased by 8 GPa and elastic modulus of austenite (EA) d3eo-f 10 creased by 8 GPa) and an increase in internal friction in the type (ISIM) samples bch=oema2t√paa2brase0od,rapwntiidothnc the √type (I) samples

Summary

Introduction

NiTi-based shape memory alloys (SMAs) have attracted much scientific attention in recent decades. One of the most promising that possesses good functional properties at high temperatures is NiTiHf. Today, NiTiHf alloy is known as a promising material because of its high cyclic stability, corrosion resistance, strength properties, and the possibility to control transformation temperatures (TTs) and functional properties through precipitation. NiTiHf alloy is known as a promising material because of its high cyclic stability, corrosion resistance, strength properties, and the possibility to control transformation temperatures (TTs) and functional properties through precipitation All these advantages make a NiTiHf system an almost ideal candidate for use in aerospace, automotive, robotic, and other industries. Another method was found to enhance the functional properties of hightemperature SMAs: stress-induced martensite aging (SIM-aging). SIM-aging is known to be the most effective for high-temperature materials, where the ratio of the martensite starting temperature (Ms) to the material’s melting point is more than 0.2 [1]

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