scholarly journals Fabrication, Structure, and Mechanical and Ultrasonic Properties of Medical Ti6Al4V Alloys Part II: Relationship between Microstructure and Mechanical Properties and Ultrasonic Properties of Ultrasonic Scalpel

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 284
Author(s):  
Zheyu He ◽  
Hao He ◽  
Jia Lou ◽  
Yimin Li ◽  
Dongyang Li ◽  
...  

In this study, the ultrasonic resonance parameters of Ti6Al4V alloys under different heat treatments are measured by an impedance analyzer. The amplitude of the specimens is measured experimentally by means of optical microscope and image analysis software. These results show that the ultrasonic properties of Ti6Al4V alloys are closely related to β phase content and elastic modulus of the alloys. The highest volume fraction of the β phase appears in the specimen treated by solid solution treatment at 960 °C is 40.2%. These alloys present the lowest average elastic modulus (~99.69 GPa) and the minimum resonant frequency (55.06 kHz) and the highest average amplitude (21.48 µm) when the testing sample length is 41.25 mm. These findings can be used to guide the design of medical Ti6Al4V alloys for ultrasonic scalpels.

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 478
Author(s):  
Zheyu He ◽  
Hao He ◽  
Jia Lou ◽  
Yimin Li ◽  
Dongyang Li ◽  
...  

Ti6Al4V alloy has been considered as a key component used in ultrasonic scalpels. In this series of papers, the fabrication, structure, and mechanical and ultrasonic properties of medical Ti6Al4V alloys suitable for ultrasonic scalpel are studied systemically. These alloys with low elastic modulus and present a typical bimodal microstructure with relatively high β phase content (~40%) and lamellar α thickness of ≤ 0.9 µm. In the first paper, the relationship between the microstructure and mechanical properties of hot-rolled Ti6Al4V alloys treated by heating treatment is discussed. In the second paper, the dependence of the ultrasonic properties on the microstructure of the heat-treated Ti6Al4V alloys is reported. With increasing solid solution temperature, the content and size of the primary α phase decrease. In contrast, the content and size of the lamellar α phase increase. Additionally, the β phase content first increases and then decreases. The microstructure of Ti6Al4V alloys could be slightly changed by aging treatment. When the solid solution treatment temperature increases to 980 °C from 960 °C, the average size of the lamellar α phase in the alloys increases by 1.1 µm. This results in a decrease in the average yield strength (93 MPa). The elastic modulus of alloys is mainly controlled by the β phase content. The microstructure of alloys by solution-treatment at 960 °C shows the highest β phase content and lowest average elastic modulus of 99.69 GPa, resulting in the minimum resonant frequency (55.06 kHz) and the highest average amplitude (21.48 µm) of the alloys at the length of 41.25 mm.


2020 ◽  
Vol 860 ◽  
pp. 218-222
Author(s):  
Della Maharani ◽  
Anawati Anawati ◽  
I. Nyoman Jujur ◽  
Damisih

The metastable β Ti-6Al-4V alloy has been used clinically as a permanent implant material owing to its suitable mechanical properties and biocompatibility. However, the alloying element V was accused of causing toxicity when released to human body fluid. In this work, Nb was used in the alloy to replace V. This study presents the characterization of microstructure and mechanical hardness of as-cast Ti-6Al-7Nb and after solution treatment. The Ti-6Al-7Nb alloy was fabricated by the centrifugal casting method. Solution treatment was carried out at 970°C for 1 hour, followed by oil quenching, and consecutively an aging treatment was applied at 500°C for 8 hours. The microstructure was studied by an optical microscope. The mechanical hardness was measured by microhardness Vickers. The results show that the mechanical hardness of the Ti-6Al-7Nb decreased from 396.2 to 377.2 HV as a result of the solution treatment. Reduction in the hardness was attributed to the phase transformation of α to the β phase during the solution treatment. The XRD analysis showed a reduction in the intensity of α phases at the (011), (012), and (020) planes in the alloy after the solution treatment. The results indicated that the microstructure and mechanical hardness of Ti-6Al7-Nb alloy were affected by the solution treatment.


2015 ◽  
Vol 641 ◽  
pp. 120-123 ◽  
Author(s):  
Robert Dąbrowski ◽  
Janusz Krawczyk ◽  
Edyta Rożniata

The results of investigations of the influence of the ageing temperature on the selected mechanical properties i.e. hardness, fracture toughness (examined by the linear elastic fracture mechanics - KIctest) and impact strength (KV) of two-phase Ti6Al7Nb alloy, are presented in the hereby paper. Investigations were performed in the ageing temperatures range: 450÷650°C of the alloy previously undercooled from the selected heating temperature (in two-phase range) - equal 970°C. The heating temperature was determined on the basis of the dilatometric curve of the alloy heating in the system ΔL = f ((T), where: ΔL – change of the sample length, T – temperature, which was then differentiated in the system: ΔL/ΔT = f (T). The dilatometer L78 R.I.T.A of the LINSEIS Company was used in the tests. Investigations of the alloy microstructure in the ageing temperatures range 450÷650°C were carried out by means of the light microscope Axiovert 200 MAT of the Carl Zeiss Company. It was found that nearly equiaxial grains of the primary α phase occur in the microstructure (of the volume fraction app. 30%) and that the volume fraction of the new lamellar α phase - formed from the supersaturated β phase - increases. With an increase of the alloy ageing temperature, in the mentioned above range, a small increase of its hardness from 305 to 324HV as well as a decrease of stress intensity factor KIcfrom 67.3 to 48.6 MPa x m1/2and impact strength (KV) from 40.2 to 31.3 J. The impact tests results were supplemented by the fractographic documentation. It was found, that the characteristic features of the fractures of impact test samples do not exhibit essential differences in dependence of the ageing temperature and material hardness. The fractographic investigations were performed by means of the scanning electron microscope NovaNanoSEM 450.


2011 ◽  
Vol 702-703 ◽  
pp. 872-875
Author(s):  
S. Banumathy ◽  
Rajiv Kumar Mandal ◽  
A.K. Singh

This work describes the development of texture during hot rolling of two alloys namely, Ti-12Nb and Ti-16Nb. The alloys have been unidirectionally hot rolled to 80 % reductions at 800°C and air cooled. Both the alloys show the presence of a² (orthorhombic) and small volume fraction of b (bcc) phases in hot rolled condition. The alloy Ti-12Nb exhibit moderate intensity texture while the alloy Ti-16Nb displays quite strong texture. The high overall intensity of texture in alloy Ti-16Nb in 80 % HR specimen can be attributed to the presence of large volume fraction of b phase in comparison to that of the alloy Ti-12Nb. This has been extended to study the textural changes after b solution treatment. This heat treatment consists of two types of phase transformations that are a² ® b ® a² and a² ® b ® a after water quenching and furnace cooling from β phase field.


2005 ◽  
Vol 488-489 ◽  
pp. 151-154
Author(s):  
Weichao Zheng ◽  
Xiao Li Sun ◽  
Peijie Li ◽  
Daben Zeng ◽  
L.B. Ber

Effect of heat treatment on the microstructure and mechanical properties of high purity MA2-1(Mg-5wt.%Al-1wt.%Zn-0.4wt.%Mn) alloy sheet were investigated. X-ray diffraction analysis indicated that the microstructure of high purity MA2-1 alloy sheet annealed consisted of α-Mg solid solution, β (Mg17Al12) phase and Al-Mn phases such as Al6Mn and Al10Mn3. β phase dissolved into α-Mg solid solution during the solution treatment and formed supersaturated α-Mg solid solution. After aging at the temperatures of 423 K, 473 K and 523 K for 12 hours, β phase precipitated from the supersaturated α-Mg solid solution. Optical microscope observation found that the grain size of the MA2-1 alloy sheet became larger after heat treatment. As a result, the mechanical properties of the MA2-1 alloy sheet such as the tensile strength and yield strength declined after the heat treatment.


2017 ◽  
Vol 898 ◽  
pp. 1156-1162
Author(s):  
Xun Wang ◽  
Chao Zhao ◽  
Yan Gen Yu ◽  
Zong Qiang Luo ◽  
Wei Wen Zhang

The effects of solution treatment on the microstructure evolution of hot-extruded Cu-15Ni-8Sn alloy were investigated by optical microscope (OM), scanning electronic microscope (SEM), differential scanning calorimetry (DSC) and tensile testing, and the effects of solution temperature and time on the mechanical properties of the alloys were analyzed. The results indicated that, the γ-phases precipitated at first and then dissolved with the extension of the solution time during solutionizing at 800 C,the volume fraction of theγ-phase reached its peak at about 1h. However when solutionizing at 860°C, theγ-phase solely dissolved gradually with the extension of the solution time . In addition, a small amount of annealing twins appeared intragranular in the process of solution treatment. The γ-phase dissolution and the grain growth of α (Cu) were the main softening factors of the alloy during the solution treatment. Through overall consideration, the optimum solution treatment was annealing at 840°Cfor 1 h.


2017 ◽  
Vol 748 ◽  
pp. 245-249
Author(s):  
Chao Duan ◽  
Jin Liang Huang

This paper studies the effect of different solution temperature and quenching medium on Microstructure and hardness of Mg-9Li-4Al-1Zn-0.5Y alloy by means of optical microscope (OM), X-ray diffraction (XRD) and hardness testing. The results show that in the solution process, the higher of the solution temperature is, more of the second phase dissolved in β phase. In the quenching process, the higher of the cooling rate is, more of the second phase dissolved in the β phase precipitates from the super-saturation β matrix, which can greatly weaken the solution strengthening effect. The hardness of the investigated alloy reaches its highest value with solution treatment at 648K and water-quenched treatment, increased from 58HB to 108HB.


2006 ◽  
Vol 306-308 ◽  
pp. 845-850 ◽  
Author(s):  
Joong-Suk Kook ◽  
Tadaharu Adachi

In this study, a manufacturing process for glass fiber reinforced plastics (GFRP) laminates was developed to improve volume fraction of fibers and mechanical properties. The manufacturing process is combination with wet lay-up and vacuum curing under atmosphere pressure for production of large and complicated structure as a leisure boat and so on. Several kinds of GFRP laminates were produced to consider optimum conditions of the process from viewpoint of volume fraction of fibers and mechanical properties. Volume fractions of fibers in GFRP laminates were measured and cross sections were observed by an optical microscope. The volume fraction in the GFRP laminate made by the suggested method was improved to 41 %, although the one made by conventional wet lay-up method was 17.7 %. Because a lot of large voids included in the laminates were drastically decreased due to the methods. For each laminate, three-point bending test was performed to measure elastic modulus and fracture toughness. Elastic modulus was improved from 5.39 GPa to 8.91 GPa with high volume fractions of fibers. Fracture toughness was improved from 8.19 MPa m1/2 to 16.6 MPa m1/2. Therefore, it was obtained that the method combined with wet lay-up and vacuum curing is easy process for manufacturing large and complicated structure to improve excellent mechanical properties and accuracy of structural shape.


Author(s):  
Hosam Alegaly Alaraby ◽  
Magdi Mohamad A Lswalhia ◽  
Tajammul Ahmed

<p class="abstract"><strong>Background:</strong> Titanium and its alloys are being extensively researched and are applied relatively in different fields of dentistry since 1970s. Its inherent advantages like high strength, ductility, low modulus of elasticity, ease of formation of oxidized surface layer, ability to retain mechanical integrity after autoclave and relatively low toxicity has led to extensive application of titanium and its alloys in implant dentistry.</p><p class="abstract"><strong>Methods:</strong> The Titanium alloy Ti-6Al-4V dental implant material used for the present study was procured from Mishra Dhatu Nigam (Midhani, Hyderabad). The mechanically polished samples were etched using Kroll’s reagent (5% hydrofluoric acid+10% nitric acid+85% water). The etched specimens were examined under optical microscope.  </p><p class="abstract"><strong>Results:</strong> The primary α phase being the low temperature phase, is stable and shows single phase microstructure. The size and volume fraction of the primary α and transformed β phases depend on the solution treatment temperatures and the subsequent rate of cooling.</p><p><strong>Conclusions:</strong> The success of the treatment modality relies on the knowledge of the properties required to employ them at the right situation. </p>


2015 ◽  
Vol 816 ◽  
pp. 804-809 ◽  
Author(s):  
Xiao Yun Song ◽  
Yong Ling Wang ◽  
Wen Jing Zhang ◽  
Song Xiao Hui ◽  
Wen Jun Ye

The effects of different duplex annealing treatments on the microstructure and mechanical properties of Ti62421S alloy plate were studied by optical microscope (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA) and tensile tests, The experimental results indicated that the original microstructure of Ti62421S was composed of primary α phase (αp) and intergranular β phase. With the increase of first-stage annealing temperature, the volume fraction of equiaxed αp phase decreased. In contrast, the content of transformed β structure (βt) increased, and the width of lamellar secondary α phase (αs) in βt increased. Consequently, the yield strength (σ0.2) and ultimate tensile strength (σb) at room temperature and 600°C increased, while the elongation (δ5) declined. After 1000°C/2h/AC+ 600°C/2h/AC duplex annealing treatment, Ti62421S alloy plate showed superior tensile properties. The values of σb and δ5 at room temperature reached 1133MPa and 6%, as well as the value of σb at 600°C exceeded 710MPa.


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