The presented work is focused on the determination of elastic constants of selected alloys of the systems Ni-Ti and Ni-Ti-Cu with use of ultrasonic methods. Sample preparation was carried out using VIM in graphite crucible in combination with pouring into graphite mould. The prepared samples were appropriately heattreated, polished into the desired shape and subjected to measurement of density and then to ultrasonic measurements. In addition to conventional methods, such as mechanical tests, also less known methods are applied. Among the specific methods we can mention dynamic mechanical analysis, dynamic super microhardness measurement, electro acoustic resonance or ultrasonic test.The group of thus tested materials includes also Ti alloys

I. Szurman

M. Kursa

R. Kocich

English

The presented work is focused on the determination of elastic constants of selected alloys of the systems Ni-Ti and
Ni-Ti-Cu with use of ultrasonic methods. Sample preparation was carried out using VIM in graphite crucible in combination
with pouring into graphite mould. The prepared samples were appropriately heattreated, polished into the
desired shape and subjected to measurement of density and then to ultrasonic measurements. In addition to conventional
methods, such as mechanical tests, also less known methods are applied. Among the specifi c methods we
can mention dynamic mechanical analysis, dynamic super microhardness measurement, electro acoustic resonance
or ultrasonic test.The group of thus tested materials includes also Ti alloys.Web of Science53336035

Szurman, Ivo

Kocich, Radim

Kursa, Miroslav

DSpace at VSB Technical University of Ostrava

357METALURGIJA 53 (2014) 3, 357-360I. SZURMAN, R. KOCICH, M. KURSAUSING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI ON THE Ti-Ni BASED ALLOYSReceived - Prispjelo: 2013-06-21Accepted - Prihvaćeno: 2013-11-20Preliminary Note – Prethodno priopćenjeISSN 0543-5846METABK 53(3) 357-360 (2014)UDC – UDK 669.295:539.32:620.179.1=111I. Szurman, R. Kocich, M. Kursa, VŠB – Technical University of Os-trava, Faculty of Metallurgy and Material Engineering, Ostrava – Po-ruba,  Czech RepublicThe presented work is focused on the determination of elastic constants of selected alloys of the systems Ni-Ti and Ni-Ti-Cu with use of ultrasonic methods. Sample preparation was carried out using VIM in graphite crucible in com-bination with pouring into graphite mould. The prepared samples were appropriately heattreated, polished into the desired shape and subjected to measurement of density and then to ultrasonic measurements. In addition to con-ventional methods, such as mechanical tests, also less known methods are applied. Among the specifi c methods we can mention dynamic mechanical analysis, dynamic super microhardness measurement, electro acoustic resonance or ultrasonic test.The group of thus tested materials includes also Ti alloys.Keywords: Ti-Ni alloys, elastic moduli, ultrasonic methods, alloys, inhomogeneitiesINTRODUCTIONAlloys based on NiTi are characterised by shape memory phenomenon generated in a certain tempera-ture interval by reversible martensitic transformation. For practical use of the shape memory effect namely the temperature height and temperature range, in which the martensitic transformation occurs, are very important. They can be affected by the chemical composition and by the choice of technology for the preparation of al-loys. Numerous works [1, 2] were already devoted to these issues. Similarly as the determination of physical and mechanical properties it is necessary to know even before the measurement of elasticity moduli the basic structural characteristics of the investigated material, e.g. whether it is a single crystal or polycrystalline ma-terial, whether it is homogeneous or heterogeneous in terms of microstructure, its size and shape (e.g. den-drites, grains), present phases, their distribution, etc. Prior to measurement of elasticity moduli it is necessary to know in single crystals the type of lattice and, if pos-sible, also crystallographic orientation in respect to the axis of the sample (usually cylinders). The elasticity moduli can then be determined in the main crystallo-graphic directions, e.g. in the directions [100], [110] and [111]. On the other hand, the physical and mechan-ical properties at the macro level in the chemically and structurally homogeneous polycrystalline materials are in all directions identical, so it is sufﬁ cient to measure and determine the properties in one direction only, i.e. also the elasticity moduli by ultrasound.EXPERIMENTALBinary and ternary alloys were selected for the ex-periment. Chemical composition of the alloys is shown in Table 1. Table 1  Chemical composition of selected experimental alloys /at %Alloy Chemical composition Ni Ti CuA 49 50 1B 51 49 0The alloys were prepared in a high-frequency vacu-um induction furnace in a graphite crucible, fully in ac-cordance with the previously published works [3 - 5]. High purity input materials were used for preparation of the alloys: Ni (C 0,01 %, Fe 0,0048 %, Al < 0,0002 %, Ti 0,0056 %, O2 0,002 %, N2 0,0002 %), Ti (C 0,025 %, Fe 0,016 %, Al < 0,002 %, Ni 0,051 %, O2 0,061 %, N2 0,0002 %), Cu (99,99 %). Casting of the alloy was per-formed into a graphite mould, in this manner the ingots with a diameter of 15 mm and a length of 300 mm were prepared. After metallurgical preparation of the alloys swaging at the temperature of 850 °C to the ﬁ nal with diameter of 5 mm was carried out. During forging an inter-stage annealing was performed. The alloys were further examined by optical microscopy (Olympus GX-51 with DP12 camera) and scanning electron micros-copy (JEOL JSM 4690 LV). We also performed deter-mination of gases by thermoevolution method (LECO TC 436) and carbon (SpecroMaxx). Using these meth-ods, it was determined that the microstructure contained small carbidic phases of the type TiC of the size of sev-eral micrometers. They resulted from the preparation of the alloys in a graphite crucible. The microstructure of 358  METALURGIJA 53 (2014) 3, 357-360I. SZURMAN et al.: USING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI...a TiNi intermetallic compound (Region 2 in Figure 1b), in which a larger amount of Cu is dissolved. We can see in the microstructure also darker smaller longitudinal formations corresponding to the phase Ti2Ni. They con-tain a smaller amount of Cu compared with the TiNi phase. There are also minor carbidic TiC type forma-tions, which correspond in Figure 1 to the Area 4. The area 1 shows the area for indicative determination of the chemical composition of the alloy by the EDX method. Chemical composition of the alloy was conﬁ rmed by this method.Figure 2a shows the microstructure of the binary al-loy B in the as cast condition, it is a cross-sectional view. The microstructure of the alloy in the as cast state is very similar to the microstructure of the alloy A. As it can be seen in Figure 2b, it is again formed by the ma-jority TiNi intermetallic phase (area 1), in which the darker areas are formed by the Ti2Ni phase. We can see here also a signiﬁ cant amount of carbidic phases of the TiC type of similar size as that of the alloy A (area 4). The area 1 (marked by rectangle) indicates the area used for indicative determination of the alloy chemical com-position. In this case too, the chemical composition was conﬁ rmed by the EDX method.the alloy also contained smaller oxide inclusions of the type oxide inclusions with the size ranging from 0,5 to 1 micrometer. No phases rich in Cu were found in sam-ples of ternary alloys. Samples of cylindrical shape with a height of 6 mm were prepared for next testing. The samples were then annealed at 850 °C for 30 minutes and cooled down in the furnace with an atmosphere of Ar with purity 99,996 %. Bases of cylindrical samples were ground in parallel to the plane. Ultrasonic meas-urement was performed only in the axial direction. For the measurement of elasticity moduli with use of ultra-sound (US) we ﬁ rst determined the samples density ρ / kg.m-3, since the modulus of elasticity is a function of the product of the material density and the square of the US velocity. The density of the samples was determined by hydrostatic method and then longitudinal (vL) and transverse (vt) US velocities were measured. These val-ues were measured in the direction perpendicular to the surface of the cylinder bases and to the vector of rota-tion polarisation of transverse wave in these areas by 360° in order to determine whether there an anisotropy of the US velocity exists in the sample, i.e. whether structural texture also exists in accordance with US measurement [6, 7]. All the measurements were per-formed in the austenite phase (B2) at room temperature. The alloys with the shape memory phenomenon might have been investigated also within the temperature range of direct and reverse martensitic transformation [8], but this was not realised in the presented work. Un-der the given temperature conditions and geometrical parameters of the samples these methods work reliably. In order to avoid measurement errors due to spatial in-homogeneities of properties we therefore realised the measurements always on three samples, and the data in tables represent average values. Difference between in-dividual measured values was only minimal.RESULTS AND DISCUSSIONMetallographic analysis and determination of contents of interstitial elementsMelting was performed with the following parame-ters. First, the furnace was evacuated to a residual pres-sure of p = 50 Pa and then ﬁ lled with Ar (6N) to the pres-sure p = 20 kPa. This process was repeated 3 times. The furnace was then evacuated to p = 2,5 Pa. Melting was carried out for 10 minutes at the output P = 10 to 19 kW, current I = 100 - 125 A, voltage of 150 - 190 V and a frequency of 3,6 to 3,7 kHz. After melting, the melt was for another approx. 10 seconds stirred by inductive cur-rents. This was followed by ﬁ lling the furnace with Ar (6N) to the pressure of several kPa and by casting of ma-terial. In all castings the content of gas (O2 and N2) and of carbon was determined in various parts of the casting, the data in the Table 2 represent average values .Figure 1 shows the microstructure of ternary alloy A. Microstructure of the alloy A is composed mainly by Table 2 Contents of gases in experimental alloys /wt. %Alloy O2 N2 C A 0,0754 0,052 0,034B 0,0638 0,046 0,025Figure 1  Microstructure of alloy A, as cast, a) optical micrograph, cross section 200x; b) SEM-BSE image359METALURGIJA 53 (2014) 3, 357-360I. SZURMAN et al.: USING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI...Ultrasonic analysisThe US method was applied on several materials among others Ti based [9 - 11]. In spite of this fact the results that could be used for direct comparison with this study are only rare. It is generally known that ten-sile tests seem to give slightly lower Young’s modulus (B) values than US methods. Table 3 summarises the results of the measurements of speciﬁ c characteristics for the alloys A and B. The modules of elasticity (E) were calculated from the average rates of US, presented in table 3 according to the following equations:E = ρv2L (3a2 - 4)/(a2 - 1),  a = vL/vt  (1)G = ρvt2     (2)B = ρ(3v2L -  4v2t)     ( 3 )      = (a2 - 2) / 2(a2 - 1)    (4)It is evident from the presented table that although the density of individual types of alloys differs only negligibly, situation is different what concerns the mod-ulus of elasticity (E) and Poisson’s ratio (). The differ-ence of 4 GPa between the samples A and B (Table 3) can serve as concrete example of this. The difference in the values  of elastic modules and in particular the dif-ference in the values  of the Poisson’s ratio of transverse contraction can already be considered signiﬁ cant and it might have been invoked either by different constitu-tion, or by the change of the physical-metallurgical pa-rameters during preparation of the samples. It is highly probable that comparatively high value of  may be re-ﬂ ected also in the parameters of the shape memory ef-fect of NiTi alloys.Table 3  The measured values of density ρ, vL longitudinal and transverse US velocity vt, modulus of elasticity E, shear modulus G, Young’s modulus in a versatile pressure B, and Poisson’s ratioAlloy ρ / kg·m-3 vL / m·s-1 vt / m·s-1A 6407,4 5201,9 1878,0B 6467,8 5301,5 1803,5E / GPa G / GPa B / GPa64,42 22,61 143,24 0,42560,37 21,05 153,72 0,435CONCLUSIONSExperimental material with quite satisfactory char-acteristics was prepared by vacuum induction melting. Satisfactory levels of interstitial impurities were found, as presented in Table 2. Using the techniques of optical and scanning electron microscopy we performed micro-structural analysis, which established that both alloys were homogeneous, free from casting defects, and the required chemical composition was conﬁ rmed by the EDX technique. The microstructure contained only small areas of the phase Ti2Ni and also carbidic phases of the type TiC (which resulted from the preparation of experimental material in a graphite crucible). The sam-ples for the next experiment were successfully prepared by swaging. The results of determination of the density of both alloys (ternary and binary) did not show any substantial differences, the determined density of the al-loys therefore corresponded to the current state of knowledge. The measured values of elastic constants in the austenitic state slightly differed for both alloys (as shown in Table 3), it can be said, however,  that the de-termined values correspond to the current state of knowledge in this ﬁ eld.AcknowledgementsThis paper was created within the framework of the project No. CZ.1.05/2.1.00/01.0040 “Regional Material Science and Technology Centre” within the operation programme “Research and Development for Innova-tions” funded from the Structural Funds and from the state budget of the Czech Republic.REFERENCES[1]  R. Kocich, M. Kursa, I. Szurman, J. Fiala. Journal of alloys and compounds. 509 (2011). 2716-2722. [2] K. Otsuka, C.M. Wayman. Shape Memory Materials, in K. Otsuka and C.M.Wayman (Eds.) Cambridge University Press. 1998. 18-34.Figure 2  Microstructure of alloy B, as cast, a) optical micrograph, cross section 200x; b) SEM-BSE image360  METALURGIJA 53 (2014) 3, 357-360I. SZURMAN et al.: USING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI...[3] Z. Zhonghua, et al. Materials Transactions. 47  (2006) 3. 661-669.[4]  R. Kocich, I. Szurman, M. Kursa, J. Fiala. Materials Scien-ce and Engineering A. 512 (2009) 1-2. p. 100-104.[5]  I. Szurman, R. Kocich, M. Kursa.  Shape Memory Alloys: Fabrication and processing. LAP LAMBERT Academic Publishing. 2012. 112 p.[6] J. Lu, Q. Hu, R. Yang. Journal of Materials Science and Technology. 25 (2009) 2.  p. 215-218.[7] X. Ren et al. Philosophical Magazine A. 79 (1999) 1. p. 31-41.[8]  T.M. Brill, S. Mittelbach, W. Assmus, M. Mulner, B. Luthi. Journal of Physics: Condensed Matter. 3 (1991). 9621-9627.[9] M. Niinomi, M. Nakai, J. Hieda. Acta Biomaterialia. 8 (2012). 3888–3903.[10]   Q. Wei, L. Wang, Y. Fu, J. Qin, W. Lu, D. Zhang. Inﬂ uence of oxygen content on microstructure and mechanical pro-perties of  Ti–Nb–Ta–Zr alloy. Materials & Design. 32 (2011) 5. 2934–9.[11] Y.L. Zhou, M.  Niinomi.  Journal of Alloys Compounds. 466 (2008). 535–542.Note:  The responsible translator for English language is Boris Škandera, Ostrava, Czech Republic

Using of ultrasonic methods for determination of the elastic moduli on the Ti-Ni based alloys

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357METALURGIJA 53 (2014) 3, 357-360I. SZURMAN, R. KOCICH, M. KURSAUSING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI ON THE Ti-Ni BASED ALLOYSReceived - Prispjelo: 2013-06-21Accepted - Prihvaćeno: 2013-11-20Preliminary Note – Prethodno priopćenjeISSN 0543-5846METABK 53(3) 357-360 (2014)UDC – UDK 669.295:539.32:620.179.1=111I. Szurman, R. Kocich, M. Kursa, VŠB – Technical University of Os-trava, Faculty of Metallurgy and Material Engineering, Ostrava – Po-ruba,  Czech RepublicThe presented work is focused on the determination of elastic constants of selected alloys of the systems Ni-Ti and Ni-Ti-Cu with use of ultrasonic methods. Sample preparation was carried out using VIM in graphite crucible in com-bination with pouring into graphite mould. The prepared samples were appropriately heattreated, polished into the desired shape and subjected to measurement of density and then to ultrasonic measurements. In addition to con-ventional methods, such as mechanical tests, also less known methods are applied. Among the specifi c methods we can mention dynamic mechanical analysis, dynamic super microhardness measurement, electro acoustic resonance or ultrasonic test.The group of thus tested materials includes also Ti alloys.Keywords: Ti-Ni alloys, elastic moduli, ultrasonic methods, alloys, inhomogeneitiesINTRODUCTIONAlloys based on NiTi are characterised by shape memory phenomenon generated in a certain tempera-ture interval by reversible martensitic transformation. For practical use of the shape memory effect namely the temperature height and temperature range, in which the martensitic transformation occurs, are very important. They can be affected by the chemical composition and by the choice of technology for the preparation of al-loys. Numerous works [1, 2] were already devoted to these issues. Similarly as the determination of physical and mechanical properties it is necessary to know even before the measurement of elasticity moduli the basic structural characteristics of the investigated material, e.g. whether it is a single crystal or polycrystalline ma-terial, whether it is homogeneous or heterogeneous in terms of microstructure, its size and shape (e.g. den-drites, grains), present phases, their distribution, etc. Prior to measurement of elasticity moduli it is necessary to know in single crystals the type of lattice and, if pos-sible, also crystallographic orientation in respect to the axis of the sample (usually cylinders). The elasticity moduli can then be determined in the main crystallo-graphic directions, e.g. in the directions [100], [110] and [111]. On the other hand, the physical and mechan-ical properties at the macro level in the chemically and structurally homogeneous polycrystalline materials are in all directions identical, so it is suffi cient to measure and determine the properties in one direction only, i.e. also the elasticity moduli by ultrasound.EXPERIMENTALBinary and ternary alloys were selected for the ex-periment. Chemical composition of the alloys is shown in Table 1. Table 1  Chemical composition of selected experimental alloys /at %Alloy Chemical composition Ni Ti CuA 49 50 1B 51 49 0The alloys were prepared in a high-frequency vacu-um induction furnace in a graphite crucible, fully in ac-cordance with the previously published works [3 - 5]. High purity input materials were used for preparation of the alloys: Ni (C 0,01 %, Fe 0,0048 %, Al < 0,0002 %, Ti 0,0056 %, O2 0,002 %, N2 0,0002 %), Ti (C 0,025 %, Fe 0,016 %, Al < 0,002 %, Ni 0,051 %, O2 0,061 %, N2 0,0002 %), Cu (99,99 %). Casting of the alloy was per-formed into a graphite mould, in this manner the ingots with a diameter of 15 mm and a length of 300 mm were prepared. After metallurgical preparation of the alloys swaging at the temperature of 850 °C to the fi nal with diameter of 5 mm was carried out. During forging an inter-stage annealing was performed. The alloys were further examined by optical microscopy (Olympus GX-51 with DP12 camera) and scanning electron micros-copy (JEOL JSM 4690 LV). We also performed deter-mination of gases by thermoevolution method (LECO TC 436) and carbon (SpecroMaxx). Using these meth-ods, it was determined that the microstructure contained small carbidic phases of the type TiC of the size of sev-eral micrometers. They resulted from the preparation of the alloys in a graphite crucible. The microstructure of 358  METALURGIJA 53 (2014) 3, 357-360I. SZURMAN et al.: USING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI...a TiNi intermetallic compound (Region 2 in Figure 1b), in which a larger amount of Cu is dissolved. We can see in the microstructure also darker smaller longitudinal formations corresponding to the phase Ti2Ni. They con-tain a smaller amount of Cu compared with the TiNi phase. There are also minor carbidic TiC type forma-tions, which correspond in Figure 1 to the Area 4. The area 1 shows the area for indicative determination of the chemical composition of the alloy by the EDX method. Chemical composition of the alloy was confi rmed by this method.Figure 2a shows the microstructure of the binary al-loy B in the as cast condition, it is a cross-sectional view. The microstructure of the alloy in the as cast state is very similar to the microstructure of the alloy A. As it can be seen in Figure 2b, it is again formed by the ma-jority TiNi intermetallic phase (area 1), in which the darker areas are formed by the Ti2Ni phase. We can see here also a signifi cant amount of carbidic phases of the TiC type of similar size as that of the alloy A (area 4). The area 1 (marked by rectangle) indicates the area used for indicative determination of the alloy chemical com-position. In this case too, the chemical composition was confi rmed by the EDX method.the alloy also contained smaller oxide inclusions of the type oxide inclusions with the size ranging from 0,5 to 1 micrometer. No phases rich in Cu were found in sam-ples of ternary alloys. Samples of cylindrical shape with a height of 6 mm were prepared for next testing. The samples were then annealed at 850 °C for 30 minutes and cooled down in the furnace with an atmosphere of Ar with purity 99,996 %. Bases of cylindrical samples were ground in parallel to the plane. Ultrasonic meas-urement was performed only in the axial direction. For the measurement of elasticity moduli with use of ultra-sound (US) we fi rst determined the samples density ρ / kg.m-3, since the modulus of elasticity is a function of the product of the material density and the square of the US velocity. The density of the samples was determined by hydrostatic method and then longitudinal (vL) and transverse (vt) US velocities were measured. These val-ues were measured in the direction perpendicular to the surface of the cylinder bases and to the vector of rota-tion polarisation of transverse wave in these areas by 360° in order to determine whether there an anisotropy of the US velocity exists in the sample, i.e. whether structural texture also exists in accordance with US measurement [6, 7]. All the measurements were per-formed in the austenite phase (B2) at room temperature. The alloys with the shape memory phenomenon might have been investigated also within the temperature range of direct and reverse martensitic transformation [8], but this was not realised in the presented work. Un-der the given temperature conditions and geometrical parameters of the samples these methods work reliably. In order to avoid measurement errors due to spatial in-homogeneities of properties we therefore realised the measurements always on three samples, and the data in tables represent average values. Difference between in-dividual measured values was only minimal.RESULTS AND DISCUSSIONMetallographic analysis and determination of contents of interstitial elementsMelting was performed with the following parame-ters. First, the furnace was evacuated to a residual pres-sure of p = 50 Pa and then fi lled with Ar (6N) to the pres-sure p = 20 kPa. This process was repeated 3 times. The furnace was then evacuated to p = 2,5 Pa. Melting was carried out for 10 minutes at the output P = 10 to 19 kW, current I = 100 - 125 A, voltage of 150 - 190 V and a frequency of 3,6 to 3,7 kHz. After melting, the melt was for another approx. 10 seconds stirred by inductive cur-rents. This was followed by fi lling the furnace with Ar (6N) to the pressure of several kPa and by casting of ma-terial. In all castings the content of gas (O2 and N2) and of carbon was determined in various parts of the casting, the data in the Table 2 represent average values .Figure 1 shows the microstructure of ternary alloy A. Microstructure of the alloy A is composed mainly by Table 2 Contents of gases in experimental alloys /wt. %Alloy O2 N2 C A 0,0754 0,052 0,034B 0,0638 0,046 0,025Figure 1  Microstructure of alloy A, as cast, a) optical micrograph, cross section 200x; b) SEM-BSE image359METALURGIJA 53 (2014) 3, 357-360I. SZURMAN et al.: USING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI...Ultrasonic analysisThe US method was applied on several materials among others Ti based [9 - 11]. In spite of this fact the results that could be used for direct comparison with this study are only rare. It is generally known that ten-sile tests seem to give slightly lower Young’s modulus (B) values than US methods. Table 3 summarises the results of the measurements of specifi c characteristics for the alloys A and B. The modules of elasticity (E) were calculated from the average rates of US, presented in table 3 according to the following equations:E = ρv2L (3a2 - 4)/(a2 - 1),  a = vL/vt  (1)G = ρvt2     (2)B = ρ(3v2L -  4v2t)     ( 3 )      = (a2 - 2) / 2(a2 - 1)    (4)It is evident from the presented table that although the density of individual types of alloys differs only negligibly, situation is different what concerns the mod-ulus of elasticity (E) and Poisson’s ratio (). The differ-ence of 4 GPa between the samples A and B (Table 3) can serve as concrete example of this. The difference in the values  of elastic modules and in particular the dif-ference in the values  of the Poisson’s ratio of transverse contraction can already be considered signifi cant and it might have been invoked either by different constitu-tion, or by the change of the physical-metallurgical pa-rameters during preparation of the samples. It is highly probable that comparatively high value of  may be re-fl ected also in the parameters of the shape memory ef-fect of NiTi alloys.Table 3  The measured values of density ρ, vL longitudinal and transverse US velocity vt, modulus of elasticity E, shear modulus G, Young’s modulus in a versatile pressure B, and Poisson’s ratioAlloy ρ / kg·m-3 vL / m·s-1 vt / m·s-1A 6407,4 5201,9 1878,0B 6467,8 5301,5 1803,5E / GPa G / GPa B / GPa64,42 22,61 143,24 0,42560,37 21,05 153,72 0,435CONCLUSIONSExperimental material with quite satisfactory char-acteristics was prepared by vacuum induction melting. Satisfactory levels of interstitial impurities were found, as presented in Table 2. Using the techniques of optical and scanning electron microscopy we performed micro-structural analysis, which established that both alloys were homogeneous, free from casting defects, and the required chemical composition was confi rmed by the EDX technique. The microstructure contained only small areas of the phase Ti2Ni and also carbidic phases of the type TiC (which resulted from the preparation of experimental material in a graphite crucible). The sam-ples for the next experiment were successfully prepared by swaging. The results of determination of the density of both alloys (ternary and binary) did not show any substantial differences, the determined density of the al-loys therefore corresponded to the current state of knowledge. The measured values of elastic constants in the austenitic state slightly differed for both alloys (as shown in Table 3), it can be said, however,  that the de-termined values correspond to the current state of knowledge in this fi eld.AcknowledgementsThis paper was created within the framework of the project No. CZ.1.05/2.1.00/01.0040 “Regional Material Science and Technology Centre” within the operation programme “Research and Development for Innova-tions” funded from the Structural Funds and from the state budget of the Czech Republic.REFERENCES[1]  R. Kocich, M. Kursa, I. Szurman, J. Fiala. Journal of alloys and compounds. 509 (2011). 2716-2722. [2] K. Otsuka, C.M. Wayman. Shape Memory Materials, in K. Otsuka and C.M.Wayman (Eds.) Cambridge University Press. 1998. 18-34.Figure 2  Microstructure of alloy B, as cast, a) optical micrograph, cross section 200x; b) SEM-BSE image360  METALURGIJA 53 (2014) 3, 357-360I. SZURMAN et al.: USING OF ULTRASONIC METHODS FOR DETERMINATION OF THE ELASTIC MODULI...[3] Z. Zhonghua, et al. Materials Transactions. 47  (2006) 3. 661-669.[4]  R. Kocich, I. Szurman, M. Kursa, J. Fiala. Materials Scien-ce and Engineering A. 512 (2009) 1-2. p. 100-104.[5]  I. Szurman, R. Kocich, M. Kursa.  Shape Memory Alloys: Fabrication and processing. LAP LAMBERT Academic Publishing. 2012. 112 p.[6] J. Lu, Q. Hu, R. Yang. Journal of Materials Science and Technology. 25 (2009) 2.  p. 215-218.[7] X. Ren et al. Philosophical Magazine A. 79 (1999) 1. p. 31-41.[8]  T.M. Brill, S. Mittelbach, W. Assmus, M. Mulner, B. Luthi. Journal of Physics: Condensed Matter. 3 (1991). 9621-9627.[9] M. Niinomi, M. Nakai, J. Hieda. Acta Biomaterialia. 8 (2012). 3888–3903.[10]   Q. Wei, L. Wang, Y. Fu, J. Qin, W. Lu, D. Zhang. Infl uence of oxygen content on microstructure and mechanical pro-perties of  Ti–Nb–Ta–Zr alloy. Materials & Design. 32 (2011) 5. 2934–9.[11] Y.L. Zhou, M.  Niinomi.  Journal of Alloys Compounds. 466 (2008). 535–542.Note:  The responsible translator for English language is Boris Škandera, Ostrava, Czech Republic

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Using of ultrasonic methods for determination of the elastic moduli on the Ti-Ni based alloys

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