Study on Interface and mechanical property of laser welding of NiTi shape memory alloy and 2A12 aluminum alloy joint with a TC4 wire

2021 ◽  
Author(s):  
Qi Cheng ◽  
Ning Guo ◽  
Di Zhang ◽  
Yunlong Fu ◽  
Shuai Zhang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Laser Welding ◽  
Shape Memory ◽  
Intermetallic Compounds ◽  
Welded Joints ◽  
Laser Power ◽  
Thermal Deformation ◽  
Fracture Load ◽  
Niti Shape Memory Alloy ◽  
Niti Sma

Abstract 2A12 aluminum alloy had the advantages of light weight and high strength. It could be used to manufacture the skin of the hypersonic aircraft. Due to the thermal deformation of fuselage and wing under long-term thermal and mechanical load, the accuracy of flight control was reduced. The shape memory effect of NiTi shape memory alloy (SMA) could be used to reduce the thermal deformation by realizing the laser welding of NiTi SMA and 2A12 aluminum alloy. According to previous studies on laser welding of NiTi SMA and TC4, the tendency to crack for the welded joints could be reduced by placing the laser beam on the side of TC4. Therefore, TC4 wire was used as the filling material. As the TC4 wire was constantly sent into the molten pool to absorb laser energy, the melting amount of NiTi SMA and 2A12 aluminum alloy were reduced. It was beneficial to reduce the formation of brittle intermetallic compounds. There were mainly the fusion zone (FZ), NiTi SMA/FZ interface, and the 2A12 aluminum alloy/FZ interface in the welded joints. With the increase of laser power, the growing distance of Ti2Ni phase also increased. In addition, the Ti-Al intermetallic compounds and the fracture load of joints firstly increased and then decreased. When the laser power was high, Ni-Al intermetallic compounds increased. This caused the decrease of fracture load of welded joints. Besides, pores caused by the burning of elements in the FZ would also weaken the fracture load of welded joints. When the laser power was 2.4 kW, more Ti-Al intermetallic compounds appeared at the interface and the maximum fracture load of welded joint was 211 N/mm. The fracture mode was intergranular brittle fracture. The heat affected zone (HAZ) with optimal mechanical properties basically retained the shape memory effect of NiTi SMA.

scholarly journals Effect of Laser Welding Parameters on Formation of NiTi Shape Memory Alloy Welds

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Wang ◽  
Xiaohong Yang ◽  
Hongguang Li ◽  
Fuzhong Cong ◽  
Yongbing Liu
Keyword(s):  
Laser Welding ◽  
Shape Memory ◽  
Welding Speed ◽  
Welded Joints ◽  
Heat Input ◽  
Continuous Wave ◽  
Niti Alloy ◽  
Welding Parameters ◽  
Niti Shape Memory Alloy ◽  
Flat Plates

In this work experimental trials of welding of NiTi flat plates with 2.0 mm thickness were conducted using a 4.5 kW continuous wave (CW) Nd:YAG laser. The influences of laser output power, welding speed, defocus amount and side-blow shielding gas flow rate on the morphology, welding depth and width, and quality of the welded seam were investigated. Meanwhile, the effects of heat input on the mechanical and functional properties of welded joints were studied. The results show that laser welding can take better formation in NiTi alloys. The matching curves with laser power and welding speed affecting different formation of welds were experimentally acquired, which can provide references for laser welding and engineering application of NiTi alloy. The heat input has obvious effects on the ultimate tensile strength (UTS) and shape memory behavior of the welded joints.

EFFECTS OF PARTICLE SIZE AND SINTERING TEMPERATURE ON SUPERELASTICITY BEHAVIOR OF NiTi SHAPE MEMORY ALLOY USING NANOINDENTATION

2021 ◽  
pp. 2150024
Author(s):  
C. VELMURUGAN ◽  
V. SENTHILKUMAR
Keyword(s):  
Particle Size ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Sintering Temperature ◽  
Niti Alloy ◽  
Indentation Load ◽  
Niti Shape Memory Alloy ◽  
Recovery Ratio ◽  
Work Recovery ◽  
Niti Sma

The present study investigates the superelasticity properties of spark plasma sintered (SPS) nickel titanium shape memory alloy (NiTi SMA) with the influence of sintering temperature and particle size. The nanoindentation is conducted on the surface of the NiTi SMA at various loads such as 100, 300 and 500[Formula: see text]mN. The nanoindentation technique determines the quantitative results of elasto-plastic properties such as depth recovery in the form of superelasticity, stiffness, hardness and work recovery ratio from load–depth ([Formula: see text]–[Formula: see text]) data during loading and unloading of the indenter. Experimental findings show that the depth and work recovery ratio increases with the decrease of indentation load and particle size. In contrast, increasing the sintering temperature exhibited a better depth and work recovery due to the removal of pores which could enhance the reverse transformation. The contact stiffness is influenced by [Formula: see text] which leads to attain a maximum stiffness at the highest load (500[Formula: see text]mN) and particle size (45[Formula: see text][Formula: see text]m) along with the lowest sintering temperature (700∘C). NiTi alloy exhibited a maximum hardness of 9.46[Formula: see text]GPa when subjected to indent at the lowest load and particle size sintered at 800∘C. The present study reveals a better superelastic behavior in NiTi SMA by reducing the particle size and indentation load associated with the enhancement of sintering temperature.

Fabrication of an Apatite/Collagen Composite Coating on the NiTi Shape Memory Alloy through Electrochemical Deposition and Coating Characterisation

2009 ◽  
Vol 618-619 ◽  
pp. 319-323 ◽  
Author(s):  
Parama Chakraborty Banerjee ◽  
Tao Sun ◽  
Jonathan H.W. Wong ◽  
Min Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Coating ◽  
Electrochemical Deposition ◽  
Room Temperature ◽  
Composite Coatings ◽  
Deposition Process ◽  
Niti Shape Memory Alloy ◽  
X Ray ◽  
Niti Sma

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.

Effect of Welding Parameters on Formation of Welds during Laser Welding of NiTi Shape Memory Alloy

2008 ◽  
Vol 35 (2) ◽  
pp. 291-296 ◽  
Author(s):  
王蔚 Wang Wei ◽  
陈俐 Chen Li ◽  
赵兴科 Zhao Xingke ◽  
黄继华 Huang Jihua
Keyword(s):  
Shape Memory Alloy ◽  
Laser Welding ◽  
Shape Memory ◽  
Welding Parameters ◽  
Niti Shape Memory Alloy

Evaluating Fretting Wear on 3D-Printed α-, β-, γ- Additives Hybridized NiTi Shape Memory Alloy

2019 ◽  
Author(s):  
O. P. Bodunde ◽  
S. M. Gao ◽  
M. Qin ◽  
W. H. Liao
Keyword(s):  
Shape Memory ◽  
Wear Test ◽  
Xrd Analysis ◽  
Fretting Wear ◽  
Niti Shape Memory Alloy ◽  
Aerospace Applications ◽  
Niti Sma ◽  
Wear Mode ◽  
3D Printed ◽  
Niti Shape Memory Alloys

Abstract Nickel-Titanium (NiTi) shape memory alloys (SMAs) are a class of promising materials for bio-implant, transportation, and aerospace applications. These interesting applications of SMA are as a result of their ability to exhibit shape memory effect (SME) and super-elasticity (SE). SMAs, especially NiTi which has been proven to have good mechanical properties, are however limited by their operational fatigue as reported in the literature. In this paper, a near equiatomic NiTi SMA was hybridized with zirconium (Zr), molybdenum (Mo) and copper (Cu), which are available and economic viable α-, β-, γ- stabilizing additives suitable for NiTi SMAs. Each of Zr, Mo, Cu were hybridized separately with the bare near equiatomic NiTi SMA. The compositional requirements for each of the sub-hybrids (NiTi-α, NiTi-β, and NiTi-γ respectively) were experimentally determined to know the optimum composition which could indicate the presence of austenitic and martensitic phases. Scan electron microscopy (SEM) was performed on each of the hybridizing additives as well as the bare equiatomic NiTi to determine their particle sizes and investigate their compatibility (between 30 and 40 microns) with the 3D printer used in the study. X-ray diffractometric (XRD) analysis also was carried out on the bare SMA and its additives to determine the presence of B2 and B19’ peaks. Afterward, NiTi-α, NiTi-β, and NiTi-γ were 3D printed to produce fretting wear test specimens and finally, the fretting wear behaviors of the NiTi hybrids were studied in detail with the objective of testing their performances under fretting wear mode as it may be required for an application. A tungsten carbide counter-body was used. The results from the characterization through XRD indicated that all of α-, β-, γ- stabilizing additives with NiTi respectively showed the presence of B2 and B19’ in the inter-metallic phases. Details of wear microstructure were reported and its information could be useful for professionals who require hybridized NiTi alloys for various engineering applications.

Laser welding of NiTi shape memory alloy: A review

2018 ◽  
Vol 31 ◽  
pp. 162-186 ◽  
Author(s):  
Mehrshad Mehrpouya ◽  
Annamaria Gisario ◽  
Mohammad Elahinia
Keyword(s):  
Shape Memory Alloy ◽  
Laser Welding ◽  
Shape Memory ◽  
Niti Shape Memory Alloy

Laser welding of NiTi shape memory alloy wires and tubes for multi-functional design applications

2016 ◽  
Vol 25 (8) ◽  
pp. 085001 ◽  
Author(s):  
Zhi Zeng ◽  
Mao Yang ◽  
João Pedro Oliveira ◽  
Di Song ◽  
Bei Peng
Keyword(s):  
Shape Memory Alloy ◽  
Laser Welding ◽  
Shape Memory ◽  
Niti Shape Memory Alloy ◽  
Functional Design
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