Hot deformation behavior of 60Nitinol (Ni60wt%–Ti40wt%) alloy: Experimental and computational studies

Dehghani, K.; Khamei, A.A.

doi:10.1016/j.msea.2009.08.059

Cited by 65 publications

(33 citation statements)

References 11 publications

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“…All flow curves presented in Fig. 1 are typical of DRX curves because they are characterized by initial work hardening up to a peak stress followed by a softening region until reaching a plateau or steady state [6,7]. However, at higher strain rates, i.e.…”

Section: Flow Curves and Microstructurementioning

confidence: 93%

“…Depending on the temperature and strain rate as well as the materials characteristics, one of them can be the controlling mechanism [6]. It was reported that dynamic recrystallization (DRX) is the dominant restoration mechanism for Ni60wt%-Ti40wt% intermetallic alloy when deformed at 950e1150 C [7]. In another research work carried out by JIANG et al, dynamic recrystallization characteristics were observed in true stressestrain curves of as-cast NiTi samples at strain rates higher than 0.01 s À1 while at strain rate of 0.001 s À1 dynamic recovery was observed rather than dynamic recrystallization [8].…”

Section: Introductionmentioning

confidence: 99%

“…The hot formability of Ni-rich NiTi alloys has not been paid enough attention though the hot workability of type 60Nitinol was recently studied by authors. It is reported that the 60Nitinol suffers from insufficient workability during its hot deformation [7]. Thus, in this research, in order to improve the hot deformability of 60Nitinol, the Cu (7.5 %wt) was added to this alloy and consequently the Ni content was reduced to 50wt% instead.…”

Section: Introductionmentioning

confidence: 99%

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A study on hot deformation behavior of Ni-42.5Ti-7.5Cu alloy

Etaati

Dehghani

2013

Materials Chemistry and Physics

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h i g h l i g h t sFlow stress behavior of Ni-42.5Ti-7.5Cu studied and modeled for the first time. The model considered the compensation of both strain and strain rate. DRX was postponed when logarithm of Z parameter was around 33 at strain rate of 0.001 s À1 and 900 C. Ti(NiCu) 2 Precipitates, formed via SIP during deformation, postponed DRX. a r t i c l e i n f o t r a c tTo investigate the hot deformation behavior of the Ni-42.5Ti-7.5Cu (wt%) alloy, hot compression tests were carried out at the temperatures from 800 C to 1000 C and at the strain rates of 0.001 s À1 to 1 s À1 . The results show that the occurrence of dynamic recrystallization (DRX) is the dominate restoration mechanism during the hot deformation of this alloy. There is an increase in peak and steady state stresses with decreasing the deformation temperature and increasing the strain rate. The experimental results were then used to determine the constants of developed constitutive equations. There is a good agreement between the measured and predicted results indicating a high accuracy of developed model. ZenereHollomon (Z) parameter, calculated based on the developed model, indicates that DRX was postponed when the logarithm of the ZenereHollomon parameter fell around 33 at strain rate of 0.001 s À1 and temperature of 900 C. This phenomenon can be regarded as the interactions between solute atoms and mobile dislocations. The established constitutive equations can be used to predict and analyze the hot deformation behavior of Ni-42.5Ti-7.5Cu alloy.

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Section: Flow Curves and Microstructurementioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A study on hot deformation behavior of Ni-42.5Ti-7.5Cu alloy

Etaati

Dehghani

2013

Materials Chemistry and Physics

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“…2, is widely used to describe the hot deformation behavior of alloys during hot shear, [30][31][32] hot compression, [33][34][35] and hot tension [36][37][38] tests:…”

Section: Constitutive Equationsmentioning

confidence: 99%

Modeling the Hot Ductility of AA6061 Aluminum Alloy After Severe Plastic Deformation

Khamei

Dehghani

Mahmudi

2015

JOM

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Solutionized AA6061 aluminum alloy was processed by equal-channel angular pressing followed by cold rolling. The hot ductility of the material was studied after severe plastic deformation. The hot tensile tests were carried out in the temperature range of 300-500°C and at the strain rates of 0.0005-0.01 s À1 . Depending on the temperature and strain rate, the applied strain level exhibited significant effects on the hot ductility, strain-rate sensitivity, and activation energy. It can be suggested that the possible mechanism dominated the hot deformation during tensile testing is dynamic recovery and dislocation creep. Constitutive equations were developed to model the hot ductility of the severe plastic deformed AA6061 alloy.

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“…There are relatively many published experiments in the field of rolling focused on the effect of ausforming (forming in the region of austenite) or marforming (forming in the area of martensite). For example, the deformation behaviour of binary NiTi alloys during hot pressure or hot tensile tests is mapped (Dehghani &Khamei, 2010 andMorakabati et al, 2010). Suzuki in (Suzuki et al, 1999) states that significant increase of hot formability can be achieved in NiTi alloys by forming at temperatures of 900° -1000°C, but there is the drawback of the above mentioned surface oxidation.…”

Section: Rollingmentioning

confidence: 99%