scholarly journals Microstructural and Cavitation Erosion Behavior of the CuAlNi Shape Memory Alloy

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 997
Author(s):  
Tatjana Volkov-Husović ◽  
Ivana Ivanić ◽  
Stjepan Kožuh ◽  
Sanja Stevanović ◽  
Milica Vlahović ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Mass Loss ◽  
Shape Memory ◽  
Cavitation Erosion ◽  
Optical Microscope ◽  
Water Quenching ◽  
Resistance Testing ◽  
Metallographic Analysis ◽  
Cavitation Resistance ◽  
Cast State

Microstructural and cavitation erosion testing was carried out on Cu-12.8Al-4.1Ni (wt. %) shape memory alloy (SMA) samples produced by continuous casting followed by heat treatment consisting of solution annealing at 885 °C for 60 min and, later, water quenching. Cavitation resistance testing was applied using a standard ultrasonic vibratory cavitation set up with stationary specimen. Surface changes during the cavitation were monitored by metallographic analysis using an optical microscope (OM), atomic force microscope (AFM), and scanning electron microscope (SEM) as well as by weight measurements. The results revealed a martensite microstructure after both casting and quenching. Microhardness value was higher after water quenching than in the as-cast state. After 420 min of cavitation exposure, a negligible mass loss was noticed for both samples. Based on the obtained results, both samples showed excellent cavitation resistance. Mass loss and morphological analysis of the formed pits indicated better cavitation resistance for the as-cast state (L).

Micro and Macromechanical Study of Stress-Induced Martensitic Transformation in a Cu-Al-Be Polycrystalline Shape Memory Alloy

2006 ◽  
Vol 509 ◽  
pp. 87-92 ◽  
Author(s):  
F.M. Sánchez ◽  
G. Pulos
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Vector Fields ◽  
Displacement Vector ◽  
Optical Microscope ◽  
Image Sequences ◽  
Tension Test ◽  
Loading Device ◽  
Stress States

An experimental investigation of the micro and macromechanical stress-induced martensitic transformation in a Cu-Al-Be polycrystalline shape memory alloy is undertaken using a uniaxial tension test. Digital images are acquired at different stress states. The image sequences are analyzed to estimate the optical flow to get displacement vector fields. The experiments are carried out on a miniature hydraulic loading device mounted under an optical microscope. The stress-strain curves and associated images show stress-induced martensitic transformation in specific grains. Displacement vector fields for the polycrystalline shape memory alloy are obtained. They are inhomogeneous due to the martensitic transformation and inter-granular interactions.

Study on Corrosion Behavior of Ti-Ni-Nb Shape Memory Alloy and 1Cr18Ni9Ti Stainless Steel Aeroplane Pipe System

2013 ◽  
Vol 668 ◽  
pp. 808-813
Author(s):  
Jun Xiu Shi ◽  
Jian Hua Liu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Nacl Solution ◽  
Corrosion Morphology ◽  
Pipe System ◽  
Pipe Coupling

The susceptibility to stress corrosion cracking (SCC) and galvanic corrosion of an aeroplane pipe made of 1Cr18Ni9Ti connected with a pipe coupling that made of Ti-Ni-Nb shape memory alloy were evaluated. SCC test was completed under simulated service environment in 6% NaCl solution through a self-designed corrosive system. Galvanic corrosion behavior of Ti-Ni-Nb/1Cr18Ni9Ti couple was conducted in 3.5% NaCl solution at 30°C, in which galvanic corrosion current (Ig) and galvanic corrosion potential (Eg) were monitored. The corrosion morphology was observed by using scanning electronic microscope (SEM) and optical microscope (OM) after SCC test and galvanic test. It was showed that no obvious corrosion was detected on the surface of the whole pipe system after the simulated test. The two metals showed excellent resistance to SCC based on the section morphology observation. The average galvanic corrosion current of 1Cr18Ni9Ti/Ti-Ni-Nb couple was 0.13µA/cm2. No obvious corrosion pitting was detected on the surface of the two alloys by OM observation. Therefore, 1Cr18Ni9Ti pipe was safely connected with Ti-Ni-Nb pipe coupling in aeroplane pipe system.

scholarly journals Cavitation erosion degradation of Belzona® coatings

2017 ◽  
Vol 17 (1) ◽  
pp. 22-33
Author(s):  
Ł. Bolewski ◽  
M. Szkodo ◽  
M. Kmieć
Keyword(s):  
Mass Loss ◽  
Steel Surface ◽  
Cavitation Erosion ◽  
Superior Performance ◽  
Distilled Water ◽  
Cavitation Resistance ◽  
Maritime Industry ◽  
Drilling Mud ◽  
P110 Steel ◽  
High Elasticity

Abstract In hydrocarbon and maritime industry there is a constant need of materials and coatings withstanding severe conditions. One of adverse phenomena present there is cavitation erosion. The paper presents evaluation of cavitation resistance of three different steel coatings. Belzona 2141 (ACR-Fluid Elastormer), 1321 (Ceramic S-Steal) and 5831 (ST-Barrier) were deployed on P110 steel and subjected to ultrasound cavitation in distilled water and drilling mud environment. According to mass loss measurements Belzona 2141 shows superior performance comparing to two other coatings and bare p110 steel surface. This is due to its high elasticity comparing to steel.

Preparation of High-Porosity NiTi Alloys by Powder Sintering with NaCl Pre-Forming

2010 ◽  
Vol 152-153 ◽  
pp. 1342-1345
Author(s):  
Hong Bo Sun ◽  
Xing Ke Zhao ◽  
Lan Lan ◽  
Ji Hua Huang ◽  
Hua Zhang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Optical Microscope ◽  
Niti Shape Memory Alloy ◽  
High Porosity ◽  
Niti Alloys ◽  
Powder Sintering ◽  
On Line ◽  
Line Repair

High-porosity NiTi shape memory alloy has pseudo-elasticity and shape memory effect for energy absorption and convenient on-line repair without replace. In this paper, high-porosity NiTi alloys with interconnected and well distributed pores were fabricated successfully by sintering, using NaCl as temporary space-holders. Optical microscope, SEM and XRD have been used to investigate the porosity and pore structures. The results show that porosity can be up to 88%.The size and porosity of the pores depend mainly on the addition of salts in the compacts, and are also related to temperature and forming pressure.

scholarly journals Determination of degradation level during cavitation erosion of zircon based ceramic

2017 ◽  
Vol 49 (2) ◽  
pp. 175-185 ◽  
Author(s):  
Marko Pavlovic ◽  
Marina Dojcinovic ◽  
Sanja Martinovic ◽  
Milica Vlahovic ◽  
Zoran Stevic ◽  
...  
Keyword(s):  
Mass Loss ◽  
Thermal Imaging ◽  
Cavitation Erosion ◽  
Mechanical Shock ◽  
Cavitation Resistance ◽  
Material Degradation ◽  
Surface Degradation ◽  
Erosion Testing ◽  
Erosion Environment

Mechanical shock of zircon based ceramic induced by cavitation erosion testing was investigated in this study. Several parameters were followed in order to determine level of material degradation during the cavitation erosion testing. Mass loss was taken as a conventional criterion for material degradation, while the level of surface degradation was evaluated by image and thermal imaging analyses. Results show high cavitation resistance of zircon ceramics and their suitability when vigorous cavitation erosion environment is expected.

scholarly journals Effect of Sn Addition on Phase Transformation Behavior of Equiatomic Ni-Ti Shape Memory Alloy

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0961
Author(s):  
Ali Abadi Aljubouri ◽  
Safa hasan Mohammed ◽  
Mudhafar ali Mohammed
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Optical Microscope ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Micro Hardness ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
Phase Transformation Behavior

Sn effect on the phase transformation behavior, microstructure, and micro hardness of equiatomic Ni-Ti shape memory alloy was studied. NiTi and NiTiSn alloys were produced using vacuum induction melting process with alloys composition (50% at. Ni, 50% at.Ti) and (Ni 48% at., Ti 50% at., Sn 2% at.). The characteristics of both alloys were investigated by utilizing Differential Scanning Calorimetry, X- ray Diffraction Analysis, Scanning Electron Microscope, optical microscope and vicker's micro hardness test. The results showed that adding Sn element leads to decrease the phase transformation temperatures evidently. Both alloy samples contain NiTi matrix phase and Ti2Ni secondary phase, but the Ti2Ni phase content decreases with Sn addition and this is one of the reasons that leads to decrease the micro hardness of alloy with adding Sn element in a noticeable manner. The micro hardness decreases from 238.74 for NiTi equiatomic alloy to 202 for NiTiSn alloy after heat treatment.

Effect of Hot-Forging on NiTi Shape Memory Alloy Fibers Reinforced Mg Alloy Composite

2007 ◽  
Vol 534-536 ◽  
pp. 873-876
Author(s):  
Qi Guo ◽  
Gang Li ◽  
Jian Ren Tang ◽  
Biao Yan
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Hot Forging ◽  
Optical Microscope ◽  
Mg Alloy ◽  
Niti Shape Memory Alloy ◽  
Alloy Matrix ◽  
The Matrix

The composite used in this paper was prepared by hot-pressing ball-milled Mg alloy powders, in which NiTi shape memory alloy fibers in a row were sandwiched. The microstructure were examined by an optical microscope, scanning electron microscope, X-ray diffraction, and transmission electron microscope to measure its microhardness and density. It is shown that the composite consisted of a homogenous matrix with uniformly distributed NiTi shape memory alloy fibers, where recrystallization took place in the Mg alloy matrix that was subjected to plastic deformation. It is known that plastic deformation is beneficial to the refinement of the grains, that is an adequate bonding forms between the matrix and fibers, the density of the composite increases after the hot-forging; its tensile strength increases significantly because of the grain refinement; the hot-forging process improves the properties of the NiTi shape memory alloy fibers reinforced Mg matrix composite.

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