MCEN90020 Advanced Metallic Materials Research Paper

MCEN90020 Advanced Metallic Materials Research Paper

Introduction:

The research proposal is basically focused on the titanium components and its alloys. Titanium shows a unique amalgamation of mechanical, physical and corrosion resistance properties. For that reason, they are useful for aerospace, industrial, chemical and energy industry services. Titanium is a metal, which has an interesting metallurgical property. It is available both in pure and alloy forms. The research procedure mainly deals with the three types of alloy products of titanium like alpha, alpha-beta and beta alloy. A mill processing methodology is needed for each of this alloy type. The T40 alloy is mainly used in the marine and chemical industry. It is basically an Alpha type pure titanium alloy. Heat treatment for the alloy is in annealed condition.” The titanium is a widely used metal for industrial purposes. The atomic nature of the metal is very tough and durable in nature. Therefore, this type of metal also used in alloys and the formation procedure is different for several alloy products. The research focuses on the detailed overview of titanium and its structure. The research project uses several methodologies for understanding the metal properly. The active deformation system also gets highlighted about titanium alloys. It also depicts the alloy composition and correlation with deformation texture (Sun et al. 2009).” It is used extensively in  the aircraft materials and also in the creation of various structures in the aviation industry. T its stability begins at 882 degree Celsius also. Alpha alloys have some good features which ensure excellent strength, oxidation resistance at a high temperature of 316 to 593-degree celsius. Basically, alpha alloys are single phase alloys and for that reason, they cannot be heat treated. Alpha beta alloys are the mixture of a high quantity of alpha and a few beta stabilisers. The transformation of beta phase generally occurs at the time of slow cooling. Ageing cycle helps to precipitate fine alpha particles from metastable beta. Beta stabilising elements are presented highly in beta alloys. This alloy passes through an ageing process and after the precipitation of the alpha stabilisers the alloy achieves great strength.

Summary of the paper:

This research paper prepares a detailed metallurgical analysis on Titanium metal for understanding the particular glide system activation at the time of deformation of the polycrystalline material. Also, their formation procedure analysed in this paper. Three types of alloys have been used to test the composition of the titanium alloys. The alloys are T40, T60 and TiAl6V4 respectively. The shear stress also has been observed for different kind of alloys. T40 alloy mainly used in Marine and Chemical industry. The starting material was processed by hot rolling followed by a series of cold rolling passes (each :/30/50%) interrupted by recrystallization steps (1 h at 993 K for TiAl6V4 and 1 h at 893 K for T40 and T60). Sheets of 1 and 3 mm thickness were produced from TiAl6V4. The main objective of this research paper is to understand the detailed metallurgical analysis of the Titanium metal. The main goal of the research is to determine the impact of the use of the titanium alloy on the structural growth of the aviation industry and also to analyse the effects of the use of the T40 alloy in the production of novice materials.  TiAl6V4 alloy consists of  a couple of phases. It holds substitution and interstitial elements of the alloy (Zaefferer, 2003, p.25). All of three above-mentioned experimented alloys are the single phase alloys of the titanium mewtal that are used in the aviation industry and also in the production of materials that are effective in the production of materials . Shear stress of different alloys has been calculated according to the basal slip, prismatic slip and pyramidal glide (Arrazola et al. 2009, p.2225). The objective is to make a clear overview about the atomic and metallurgical properties of Titanium.

Titanium is a widely used metal for industrial purposes. The atomic nature of the metal is very tough and durable in nature. Therefore, this type of metal also used in alloys and the formation procedure is different for several alloy products. The research focuses on the detailed overview of titanium and its structure.

The research project uses several methodologies for understanding the metal properly. The active deformation system also gets highlighted about titanium alloys. It also depicts the alloy composition and correlation with deformation texture (Sun et al. 2009, p.566). This research does not follow the conventional method for evaluating the deformation system of the metal, rather a computer program has been  developed to execute it. The orientation of the crystal controls simulation of the microscopic diffraction mode. Determination of twinning systems is possible by the crystal’s misoriented calculations. Twinning systems and active glide have been studied on the titanium alloys through transmission electron microscopy.

For a huge material, the result is not fully applicable, but it provides some good results on the metallurgical analysis. The main result shows that in TiAl6V4 basal slip  critical resolved shear stress is lower than the prismatic slip. Also, for the pyramidal glide, the shear stress is very low and it is two times greater than the prismatic slip. The c -type texture also formed by the strong basal glide. In the case of T40 alloy shear stress for (c+a) glide is thirteen times greater than the prismatic glide. The titanium alloys are the type of metals that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness (even at extreme temperatures). They can withstand high-pressurized strengths and are very much helpful in the aviation industry. It also helps in the production of myriad materials that can be further used in the production of strong alloys. They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. In the context of T60, it can be said that Twinning is got suppressed by the content of high oxygen and (c+a) glide gets reduced by the oxygen content. The t -type texture formed by the combination of (c+a) and basal glide (Akman et al. 2009, p.3710). 

The experiment mainly performed on the  calculation of resolved shear stress. The shear stress of the metal mainly calculated according to the type of the alloy. These actually shows the characteristic of titanium.

Understanding:

The quantifying approach actually elaborates the shear stress and its calculation procedures for resolving it from the metal. The crystal orientation and deformation procedure of titanium also get highlighted here. The polycrystal is treated as a series of isolated single crystals. The main highlighted areas of the research is to identify the small deformations in the production of the titanium alloys and also in the composition of the alloys of the titanium metal. It also focuses on the tensile strength and the high volatility and is also concerned about the stress state of the titanium metal. Resolved shear stress providing the deformation system that are calculated in the summation of the shear contribution of several stress tensor components are also discussed here. The main deformation modes that are present in the formation of the titanium alloys, including slip and twinning, in two grads of Ti and Ti64 are of optimum importance. Different slip systems were activated depending on chemical composition (in particular the presence of O), orientation of grains with respect to rolling direction and, in case of Ti64, presence of beta phase. The shear stress is equivalent to the multiplication of the summation of the two things, where the main element is the matrix elements deducted from the Schmid factor (Ginting and Nouari, 2009, p.330). The value of i belongs from 0 to 3 and the value of j belongs to 0 to 3. The generalised Schmid factor help to derive the matrix elements from the crystal orientation. Actually shear analysis is the base of this experiment. The twinning plane also gets multiplied to calculate the matrix elements. The research also uses a cartesian coordinate system and vector geometry (Poondlaet al. 2009, p.165). For the calculation process the stress tensors have been considered as 1 for uniaxial and biaxial tension. The implementation or the representation of the glide system families take the help of grain maps provided with different shadings. For most crystal orientation the Sachs model recommends single slip. It happened at the beginning of the deformation procedure. At the early stage of the deformation, the crystal rotation used to be small. The constraints for differently deforming neighbouring crystals are essential and the presence of poly slip confirms that. Based on the determined crystal orientation, the study allows to simulate of the diffraction mode of the microscopic formulation of the titanium alloy.. In this way, sample tilt angles under which well-defined two-beam conditions are achieved can be determined first on the computer. These angles are transferred to the microscope goniometer while observing the sample in imaging mode. In this way, sample drift due to non-eucentric tilt can be easily corrected. Line directions u and the positions of glide bands are measured by automation of the geometrical measurements of dislocation images under different tilt angles. Twinning systems are determined by misorientation calculations between two crystals. The use of the computer program allowed the determination of a larger number of dislocations and twins and the investigations may therefore be statistically more meaningful than other studies. However, some inherent limitations of the TEM method of thin foils should be kept in mind: generally, due to the small volume investigated in TEM, the results have only limited applicability for the bulk material. In the work reported here, however, good agreement between locally and globally measured textures gives confidence in the reliability of the results. The shear component of stress has been considered as an only component according to the Sachs model. A homogeneous dislocation distribution in the grain interior has been observed throughout this research. It is the only slightly deformed material, which has been observed. On the contrary, the biaxial deformation goes up to 5 percent and it shows the distribution of heterogeneous dislocation.

In this research, the samples like T601B for T60, T401B for T40 and TA1B for TiAl6V4 show equal shear stress. In prismatic glide the shear stress values are lower compared to other glides. In the case of basal and pyramidal glide systems, the shear values are highest. The sample of T40 shows the high quantity of pyramidal glide systems (Froes and Eylon, 2013, p.507). The c axis’s strong tilt explains this and comparatively delivers 25 percent higher output. Therefore, from T40 sample no conclusion can be drawn with respect to critical resolved shear stress. With respect to the sheared stress of resolved form according to pyramidal and prismatic glide, heterogeneous dislocation structure has been observed in homogeneously distributed pyramidal glide dislocations and for the long and straight basal glide dislocations. In T401B there is frequent appearance of pyramidal glide dislocations with respect to TA1B. For the accommodation of c-deformation components, the formation of twins is controlled. For the growth of the twins, zonal dislocations are mandatory.

By this approach, the oxygen gets eliminated from the material (Zhang et al. 2009, p.5368).

Critical analysis:

This study mainly deals with the active glide and twinning of titanium alloy with the help of transmission electron microscopy. Three types of titanium alloy mainly used in this research like T40 alloy with titanium and 1000 ppm of oxygen, T60 alloy with titanium and 2000 ppm of oxygen and TiAl6V4. They are deformed up to 5 percent with the direction of uniaxial and biaxial tension. The finding mainly deals with the appropriate glide system, which activated at the time of deformation of polycrystalline material and their behaviour in accordance with the cold rolling textures’ formation (Brunette et al. 2012, p.50). Titanium has been chosen for the study because of the hexagonal crystal structure. It also develops sharp deformation texturesThe metals related to cubic crystal symmetry is unevenly distributed on the pole sphere, which shows several critical resolved shear stresses. The existing components are interstitial as well as substitutional in nature. It plays major role in controlling  the shear stress of the different deformation systems. From this research mainly the different characteristics of several titanium alloys have been explored. It shows the essential deformation mechanism of hexagonal metals and about its effect with respect to cold rolling texture evaluation. It demonstrates the calculation of texture of c-type. This c-type texture is associated with (0001)-poles. These poles are parallel to the cross direction. It can also be said that t-type texture, (0001)-poles are bent in the direction of opposites. It is not clear properly that what are the exact deformation systems activated in a polycrystal at the time of straining. Also, it can be stated that the deformations are associated with (c)-component. However, they have their limitations. Therefore, the research project tries to find the exact reason behind that. Mainly three types of titanium alloys have been chosen for the research study for the purpose of measuring the extent of influence made by elements which are chemical. The procedure selected for the execution of the research is Transmission electron microscopy. With the help of this procedure, several things have been determined like glide plan of dislocations, Burger vector along with types. The characterising twinning systems can also be included in the list. The provided data sometimes help to calculate the normalised critical resolved shear stress. There is a provision for the comparison of the values for the resolved shear stress (Collings, 2013, p.62).

Three alloys of titanium have been considered for this research and two of them are single phase and the other is two phase. Two of them like T40 and T60 are consisted consisting titanium in absolute form and a combination of oxygen. Alloy TiAl6V4 is two phase and consisted with Al (Aluminium) and V with a combination of interstitial oxygen. The hexagonal close packing of this alloy is almost 10 percent of body-centred cubic phase in equilibrium. The research follows a smart method to measure the deformation systems. Conventional methods have been avoided due to the time consumption and complications. The traditional approach also restricts the concluding factors. A computer generated programming technique has been developed for the execution. The microscope is generating the result according to the crystal orientation. The tilt angle with two beams phase has been considered for the technical mapping of the project. The transformation of the angles to the microscope goniometer at the time of the observations of the sample ensures the accuracy of the research (Peters and Paqué 2010, p.45). This method takes corrective measure towards the on-eccentric tilt. The study shows some X-ray pole figures of the three types of alloys, where sample shots depict the chemical composition, sheet thickness, deformation mode and the angles. The following table illustrates the different factors highlighted in the X-ray pole figures.

(Source: Zaefferer, 2003, p.3)

The research project elaborates the deformation systems through various factors. The (a) screw classifies all screw dislocations except the glide planes, which is not clearly decided in the project. The other (a) dislocations, almost 50 percent explored the screw character, but there are some uncertainties to decide the glide plane from the glide bands..

Suggested improvement:

Titanium alloys have a huge demand in several industries in spite of its high price. This is a tough and durable metal, which has a great metallurgical property. The research mainly deals with two single phase alloys and one-two phase alloy of titanium. The main aim of the study is to find out the glide which is active. Moreover, the emphasis has been laid on finding the system of twinning. In both of the cases, methods of transmitting electron microscopy are to be used in an efficient manner. This method has been considered for learning the characteristics of  titanium alloys. In this study, the (c + a) glide systems are rarely activated and the occurrence of twinning systems are null. During the experiment 1, mm sheet is used from TiAl6V4 and it is a recrystallised sheet. On the other hand, 3 mm sheet which is partially recrystallized shows comparatively less beta-phase. The amalgamation of alpha, alpha-beta and beta alloys do not form a common outcome. Therefore, the characteristics are not completely about the titanium metal. It is according to the different alloys used in the process. The usage of Burgers vector is also limited in here. The estimation of glide plane needs additional measurements according to the geometrical positions of the glide bands. Therefore those points need to be checked for further experimentation on titanium products. Another type of alloys should be considered to get a proper overview about titanium. The sample size needs to be more unique and compact in nature for the computer testing process. The flexibility of the alloys is measured here, but corrosion of the metal has not been considered as an important factor. More metallurgical properties according to the periodic table should be included in this research work. More different slip systems need to be calculated properly from a single grain. The different flexibility of the three alloys give different results, therefore uniformity of the research should be maintained to reach a common conclusion.

Summary and conclusions:

Deformation mechanisms in polycrystalline samples of different titanium alloys have been studied by transmission electron microscopy. The aim of this report or this study was to understand in more detail, which deformation systems are actually activated in these alloys. It also aims as to how the observed deformation textures are related to them. An attempt was made to gain information about the relative values of critical resolved shear stresses (/t? c; relative to the a prismatic glide system) of different deformation systems. Uniaxial or biaxial expansion and different initial textures led to a variety of stress states in the samples.  Three types of titanium alloy used in the research to explain the different phases and glides of the material. The T60 alloy has relatively low flexibility and it is the effect of minimal deformation containing C components. In addition, it results up to high resolved shear stress. Also, the less mentioned t-type texture is due to the huge presence of basal slip. T40 has a higher flexibility than T60, which has been demonstrated through the lower critical shear stresses. It is to be noted that TiAl6V4 is having high rate of flexibility due to the size of the grains. In fact, the beta-phase being prioritized in time of deformation that contains the c-components. Deoxidation also performed here. 

Figures and tables:

A table is given below according to the proper understanding of physical and mechanical properties of elementary titanium.

(Source: Collings, 201, p.62)

Reference List:

Akman, E., Demir, A., Canel, T. and S?nmazçelik, T., 2009. Laser welding of Ti6Al4V titanium alloys. Journal of materials processing technology, 209(8), pp.3705-3713.

Arrazola, P.J., Garay, A., Iriarte, L.M., Armendia, M., Marya, S. and Le Maitre, F., 2009. Machinability of titanium alloys (Ti6Al4V and Ti555. 3).Journal of materials processing technology, 209(5), pp.2223-2230.

Brunette, D.M., Tengvall, P., Textor, M. and Thomsen, P. eds., 2012.Titanium in medicine: material science, surface science, engineering, biological responses and medical applications. Springer Science & Business Media.

Collings, E.W., 2013. Applied Superconductivity, Metallurgy, and Physics of Titanium Alloys: Fundamentals Alloy Superconductors: Their Metallurgical, Physical, and Magnetic-Mixed-State Properties. Springer Science & Business Media.

Froes, F.H. and Eylon, D., 2013. Powder metallurgy of titanium alloys.International Materials Reviews.

Ginting, A. and Nouari, M., 2009. Surface integrity of dry machined titanium alloys. International Journal of Machine Tools and Manufacture, 49(3), pp.325-332.

Peters, O.A. and Paqué, F., 2010. Current developments in rotary root canal instrument technology and clinical use: A review. Quintessence International, 41(6).

Poondla, N., Srivatsan, T.S., Patnaik, A. and Petraroli, M., 2009. A study of the microstructure and hardness of two titanium alloys: Commercially pure and Ti–6Al–4V. Journal of Alloys and Compounds, 486(1), pp.162-167.

Sun, S., Brandt, M. and Dargusch, M.S., 2009. Characteristics of cutting forces and chip formation in machining of titanium alloys. International Journal of Machine Tools and Manufacture, 49(7), pp.561-568.

Zaefferer, S., 2003. A study of active deformation systems in titanium alloys: dependence on alloy composition and correlation with deformation texture. Materials Science and Engineering: A, 344(1), pp.20-30.

Zhang, W., Liu, Y., Li, H.Z., Li, Z., Wang, H.J. and Liu, B., 2009. Constitutive modeling and processing map for elevated temperature flow behaviors of a powder metallurgy titanium aluminide alloy. Journal of Materials Processing Technology, 209(12), pp.5363-5370.