As-built Microstructure Research Articles

The role of heat treatments on wear behaviour of 316L stainless steel produced by additive manufacturing

• 316L samples were produced by Additive Manufacturing method. • Heat treatment was applied to the samples to examine the microstructure changes. • Heat treatments were found to affect the wear behavior of the samples. • The wear rate is reduced by heat treatment at 650 °C. • Increased heat treatment temperature deteriorates wear resistance. In this study, 316L stainless steel (SS) samples were produced using Direct Laser Metal Sintering (DMLS) method with standard parameters. Specimens were heat-treated at 650, 950, and 1150 °C for 2 h following the DMLS process. Effects of the heat treatments on the properties of DMLS parts were examined by microstructure, hardness, and wear tests. Microstructural properties were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) analysis. Hardness changes were determined by the Vickers hardness (HV) method. The results showed that the as-built microstructure of DMLS/316L SS deteriorated with the increase in heat treatment temperature. Moreover, heat treatment processes caused a decrease in hardness and wear resistance.

Heat Treatment, Microstructure and Corrosion Relationship on 316L SS Produced by AM

ABSTRACT In this study, 316L stainless steel (SS) samples produced with standard parameters using the Additive Manufacturing method were heat treated with different parameters, and the effects of heat treatment on the microstructure, phase changes, hardness, porosity, and corrosion of the material were examined in detail. The results showed that the as-built microstructure of 316L stainless steel material produced by Additive Manufacturing deteriorated as the heat treatment temperature increased and the hardness decreased. The corrosion resistance of the material increased. The best corrosion resistance was obtained from heat treatment at 1150°C for 2 h.

Microstructure control during deposition and post-treatment to optimize mechanical properties of wire-arc additively manufactured 17-4 PH stainless steel

The solidification and microstructural evolution during deposition, as well as the structural evolution during post heat treatment, determine the mechanical properties of wire-arc additively manufactured maraging stainless steels. In the present work, we tune the austenite reversion and nanoscale precipitation during post heat treatment and achieve an excellent combination of strength and ductility (ultimate tensile strength ~1340 MPa and uniform elongation ~10.5 %). The structural evolution is studied through computational thermodynamics, electron microscopy, in situ small-angle neutron scattering, and synchrotron X-ray diffraction. The as-built microstructure is composed of mainly martensite and retained austenite (~30 vol%) together with a minor fraction of δ-ferrite, M 23 C 6, Nb(C, N), spherical and ellipsoidal Cu precipitates and some inclusions. The presence of these phases cannot be fully predicted by the Scheil-Gulliver model due to the complicated thermal history and non-homogenous elemental distribution. The reverted austenite formed during the post heat treatments has high stability and fine grain size (~1 µm), which contributes to the excellent ductility, while the nanoscale precipitation hardening contributes to the achieved high strength.

Surface finish, microhardness and microstructure of laser metal deposited 17-4PH stainless steel

Laser metal deposition is a metal-based additive manufacturing technology. It is a very sensitive and complex process because of the different process parameters involved and the interrelations between these parameters. A thorough understanding of the underlying physics of the process is essential in developing a comprehensive database of the properties of materials processed with this technology. The main objective of this study was to investigate the effect of laser power on a laser-deposited 17-4 precipitation hardenable stainless steel alloy. The as-built microstructure, phase composition, microhardness and surface finish were analysed. The results show that a defect-free sample with good metallurgical bonding and minimal dilution can be produced using high laser power in the range 1400–2600 W and a scanning speed of 0.6 m/s. The microstructure in the clad layer was dominated by martensite and an improvement in surface finish and maximum hardness was observed with increased laser power. Significance: To fully benefit from the additive manufacturing technology, a comprehensive database of the material properties of alloys produced with this technology is required. This study expands on the body of knowledge related to the additive manufacturing of a 17-4PH stainless steel alloy, particularly highlighting the possibility of producing fully dense parts using higher laser power and scanning speed. These two parameters could significantly reduce the build time.

Dislocation-obstacle interaction evolution in rate dependent plasticity of AlSi10Mg as-built microstructure by laser powder bed fusion

Novel microstructural features obtained from laser powder bed fusion methods challenge our understanding of the rate controlling mechanisms for plasticity which are important for structural applications. The strain rate dependent plasticity of as-built AlSi10Mg laser powder bed fusion samples was systematically studied as a function of stress state (tension and compression) and strain rate at 293 and 78 K. Utilizing constant strain-rate and rate-change testing methodologies, a strong dependence of flow stress on strain rate was revealed for both stress states. The compressive yield stresses have a potent strain rate sensitivity in both quasi-static (10−4-10−1 s−1) and medium-dynamic (1-5 s−1) strain rate regimes. A positive strain rate sensitivity was observed in all strain rates except for a shift to negative values in the 10−2-10−1 s−1 range for both tensile and compression states. This negative strain rate sensitivity was correlated with the deformation-induced microstructural evolution, i.e., manifested as a gradual transition in the dominant dislocation-precipitate interaction mechanism from shearing to looping, along with the disappearance of dislocation-solute interaction in the form of dynamic strain aging (DSA). The precise measurement of activation volume evolution with flow stress further confirmed the transition from shearing to looping in the 10−2-10−1 s−1 range.

Very-high-cycle fatigue induced growth and amorphization of Si particles in additively manufactured AlSi10Mg alloy: Dependence of applied stress ratio

The microstructural evolution at the fracture surface in response to very-high-cycle fatigue (VHCF) under stress ratios (R) of −1 and 0.5 in an AlSi10Mg alloy produced by Laser Powder Bed Fusion was investigated. The results show that appreciable growth of the Si precipitates at the cellular network boundaries in the as-built microstructure was observed under R = −1. Moreover, significant amorphization of the initial crystalline Si precipitates occurred in the vicinity of the fracture surface under this condition. A layer of fine Al grains was developed in the “fish-eye” region of the fracture surface. These microstructural responses are rationalized by the generation of lattice defects including dislocations and sub-grain boundaries during cyclic pressing of crack surfaces under R = −1, which mediates the Si solute diffusion and re-precipitation in the alloy as well as the amorphization of initial Si crystalline precipitation. In contrast, far fewer dislocations were observed near the crack surfaces under R = 0.5, which is attributed to the absence of cyclic pressing of crack surfaces and severe plastic deformation in this scenario. This work provides insights into the stress ratio dependence of the microstructural evolution in the fatigued Al alloys. The obtained knowledge is useful for future understanding of the fatigue failure in Al alloys produced by additive manufacturing.

Influence of deposition strategy and heat treatment on mechanical properties and microstructure of 2319 aluminium WAAM components

There is an increasing interest in additive manufacturing of high strength aluminium alloys built with wire and arc additive manufacturing (WAAM) technologies. Al-Cu alloys are susceptible to hot cracking, however, pulse advanced cold metal transfer (CMT-PADV) welding process ensures a low heat input that avoids this defect while reducing the part porosity. This study has demonstrated that porosity below 1 % does not affect mechanical properties of 2319 WAAM walls, whereas the as-built microstructure and applied heat treatment highly influence the properties obtained. Without interlayer dwell time, a fine uniformly distributed equiaxed microstructure is obtained, however, if an interlayer arc stop period is applied, columnar dendritic grains in the interlayer zone is obtained. Heat treatment with low aging temperature and time demonstrated not to be suitable to ensure high mechanical properties and low anisotropy. Instead, if 190 °C and 26-hour aging heat treatment is used, properties up to 324 MPa for yield stress, 452 MPa tensile strength and 8 % elongation can be achieved perpendicularly to the building direction with anisotropy of 1 %, 2 % and 46 %, respectively, for the manufacturing conditions that avoided columnar grains. This fact was critical to ensure highest strength and ductility values and low anisotropy.

Optimization of Laser Metal Deposition Process for 2205 Duplex Stainless Steel

This work aims to optimize the process parameters for laser based DED manufacturing of a water jet impeller with critical requirements to material and mechanical properties. The concerned material is 2205 duplex stainless steel with balanced ferrite-austenite microstructure. The optimization approach of the processing parameters relies on the assessment of their effect on microstructure and mechanical properties versus the requirements set by the maritime industry. The work aims to achieve an as-built microstructure with the required ferrite-austenite balance and mechanical properties, without the need for post-processing heat treatment. The work particularly focuses on the influence of the deposition speed of the DED process. The results show that duplex stainless steel with a 50-50 ferrite-austenite balance can be achieved directly from the DED process. A high deposition speed produced fine-grained microstructure resulting in a high tensile strength and toughness, well above the set requirements. However, it reduced the ductility, represented by tensile elongation due to the formation of welding defects. Reducing the deposition speed by 20% eliminated the welding defects but resulted in the formation of a distinct microstructure with coarse grains, elongated in the deposited layer. This microstructure improved the tensile elongation, but strongly reduced the toughness, represented by Charpy V impact energy values. The coarse grains in the deposited layer facilitated a fast fracture propagation initiated by the placement of the Charpy V notch. However, the presented results demonstrate the great potential for manufacturing duplex stainless steels by DED, where a suitable microstructure for optimal mechanical performance can be obtained by narrowing the optimization windows on the process parameters.

Attainment of favorable microstructure for residual stress reduction through high-temperature heat treatment on additive manufactured inconel 718 alloy

Mitigation of residual stress in additive manufactured metal parts through post-heat treatment helps enhancement of life during service. The present work aims to investigate the effect of stress-relieving heat treatment (SRHT) at 1065 °C on microstructural changes, residual stress patterns, and mechanical properties of Inconel 718 (IN718) blocks fabricated through use of the laser-based powder bed fusion (L-PBF) process. The X-ray diffraction technique known as cos α method was used to capture the Debye ring for the measurement of surface residual stress. Dissolution of the columnar dendrites along with laves phases in the interdendritic region was seen after SRHT. The resultant microstructure showed partially recrystallized grains along with the formation of annealing twins and strengthening phases such as γ’, γ’’, and tiny metal carbides. The residual stress on the top surface of as-built sample was found to be 77% higher on the corners compared to the center region. The distribution of residual stress was seen as not uniform in the as-built condition. The SRHT sample showed uniform distribution of compressive residual stresses in all the locations. This phenomenon was due to the diffusion of atoms present in the high-stress regions migrated to low-stress regions until attaining their equilibrium. The combination of face centered cubic (FCC) and hexagonal lattices in as-built microstructure led to misfit strain between the grains. After SRHT, microstructure of IN718 experienced relaxation of residual stresses due to the transformation of hexagonal structured laves phase into the body-centered tetragonal (BCT) γ’’and FCC-structured γ’ phases. Furthermore, SRHT significantly alters the mechanical properties of IN718 alloy causing a 23.03% increase in average hardness and a 21.04% increase in tensile strength.

Tempering of an additively manufactured microsegregated hot-work tool steel: A high-temperature synchrotron X-ray diffraction study

Rapidly solidified microstructures, produced by concentrated heat sources, have gained increasing attention due to the widespread expansion of additive manufacturing techniques. In laser powder bed fusion of tool steels, the as-built microstructure consists of a microsegregated network of cell-like walls decorated with retained austenite (RA). This inhomogeneous elemental distribution leads to phase transformation sequences dictated by local – instead of global – equilibrium. This work uses synchrotron X-ray diffraction to study the kinetics of retained austenite decomposition during tempering of a microsegregated as-built AISI H13 tool steel. The RA decomposition products are also characterized by hardness tests, scanning electron microscopy, and atom probe tomography. Present results evidence the formation of high temperature para-equilibrium (T < 650 °C) or equilibrium (T ≥ 650 °C) microstructures. The para-equilibrium microstructural path evidences isothermally stable RA, which transforms into fresh martensite upon cooling due to carbon depletion. However, the cell-like microsegregation arrangement is retained due to insufficient homogenization of substitutional elements. The equilibrium microstructural path results in isothermal transformation of RA into ferrite + carbides, as well as dissolution of the cell-like microsegregation structure. These results provide insights towards the understanding and development of optimized heat treatment cycles appropriate for such increasingly common inhomogeneous microstructures. The results are relevant not only to laser powder bed fusion, but also to other localized melting/remelting processes with associated high cooling rates.

Towards creep property improvement of selective laser melted Ni-based superalloy IN738LC

• SLM IN738LC superalloy was treated with unconventional two-step heating schemes. • The 950 °C first step was found the most effective in redistributing the carbides. • Carbide redistribution significantly reduced grain boundary pinning and promoted grain growth. • Larger grain size led to 56% to 339% increments in creep life depending on creep strength. Nickel-based superalloy IN738LC produced by selective laser melting (SLM) exhibits inferior high-temperature creep properties than its cast counterparts due to relatively smaller grain size, particularly for the plane normal to the building direction. This work studied effects of post heating strategy on the microstructure and especially the grain size to improve the high temperature creep resistance. The as-built microstructure exhibited a fine grain size and large quantities of M C carbides that could effectively hinder grain growth. It was found that unconventional two-step heat treatments could lead to substantial grain growth, and the effect is particularly prominent at a specific temperature. The ease of grain growth was explained after classifying the microstructural evolution (boundary carbide transformation) during each heating step and related to the reduced grain boundary pinning force from M C carbides. Creep tests validated the effect of the new heat treatment scheme on the SLM-processed IN738LC at 850 °C. An extended creep fracture life (1.5 to 4 times improvement) and lower secondary creep rates were achieved with samples subjected to the newly optimized two-step heat treatment. The complete creep curves are also firstly presented for SLM-IN738LC, confirming the effectiveness of grain growth and highlighting the importance of dedicated heat treatment for SLM superalloys.

Linkage of Macro- and Microscale Modeling Tools for Additive Manufacturing of Steels

Additive manufacturing (AM) offers several benefits including the capability to produce unique microstructures, geometrical freedom allowing for material and energy savings, and easy production lines with fewer post-processing steps. However, AM processes are complex and phenomena occurring at different length and time scales need to be understood and controlled to avoid challenges with, for example, defects, residual stresses, distortions, and alloy restrictions. To overcome some of these challenges and to have more control over the final product, computational tools for different length scales need to be combined. In this work, an 18Ni300 maraging steel part is studied to understand the link between the process parameters and the as-built microstructure. The temperature evolution during laser powder bed fusion is simulated using the MSC simulation software Simufact Additive. This result is then linked to microscale models within the Thermo-Calc software package to predict the elemental micro-segregation, martensite start (Ms) temperature, and martensite fraction. The different values of the key process parameters such as laser speed, laser power, heating efficiency, and baseplate temperature are considered, leading to different thermal histories. The thermal histories affect the elemental segregation across the solidification structure, which in turn results in different Ms temperatures at different locations of the built part. It is found that higher laser energy generally causes higher temperatures and higher cooling rates, which results in a larger degree of elemental segregation and lower Ms temperatures in segregated regions. Furthermore, the segregated regions are predicted to have Ms temperatures below 200°C, which would result in retained austenite when using a baseplate temperature of 200°C. On the other hand, by using a baseplate temperature of 100°C, all regions would reach temperatures below the Ms temperature, and an almost fully martensitic structure would be possible. In summary, it is demonstrated how the linkage of macro- and microscale modeling tools for AM can be used to optimize the process and produce the desired microstructure, thereby achieving the desired mechanical properties.

Room temperature strain rate sensitivity of as-built 3D printed AlSi10Mg by laser powder bed fusion

Tensile and compression loading behavior of as-built AlSi10Mg alloy printed by laser powder bed fusion were studied at quasi-static to medium strain-rate regimes. A non-linear strain rate sensitivity behaviour was observed at all strain rates, a response linked to the extra-fine, non-equilibrium as-built microstructure. For both loading conditions, except for a negative strain rate sensitivity in 10−2–10−1 1/s range, a positive trend was observed. At the equivalent strain of 0.04, a strain rate sensitivity parameter of 0.010 and 0.019 (in 10−4–10−2 1/s range) was measured for tensile and compression loading, respectively, indicating a strong dependency especially in compression. For the medium regime (1–5 1/s), the strain rate sensitivity parameter in compression was further increased to 0.046.

Microstructure and mechanical performance of zirconium, manufactured by selective laser melting

Additive manufacturing as an innovative material fabrication technique has been attracting increasing attention from academia and industry in recent years. However, intensive studies on additive manufacturing of zirconium and its alloy are very scarce due to the challenge of fabrication technology. Herein, commercially pure zirconium (CP–Zr) components with high mechanical properties in terms of strength and plasticity were successfully manufactured by selective laser melting (SLM) under an argon atmosphere. The microscopic characteristics and mechanical properties of as-processed CP-Zr were comprehensively investigated by the means of optical microscope (OM), transmission electron microscope (TEM) and universal tensile testing machine. The characterization experiments indicated that the as-built microstructure of CP-Zr was composed of a large amount of ultra-fine α' martensite locating inside the columnar prior β grains, and massive dislocations and twins distributing in martensite or matrix. Based on the tensile testing, the as-built samples achieved a great ultimate tensile strength of 746.3 MPa and a high elongation of 27.1%. Due to the formation of ultra-fine microstructure and the synergistic effect of dislocations and twins, the strength and plasticity of as-built objects are 96% and 69% higher than the wrought CP-Zr cubes required in ASTM-523, respectively. In this work, a near-net shape method was innovatively proposed for fabricating zirconium and its alloy components. As well, a perspective insight was provided for investigating the strengthening and deformation mechanism of SLM-manufactured CP-Zr.

On as-built microstructure and necessity of solution treatment in additively manufactured Inconel 939

ABSTRACT Increased adoption of additively manufactured superalloys has led to the consideration of revised heat treatment approaches for these materials. The rapid cooling during additive manufacturing processes has been seen to suppress gamma prime (γ′) precipitation, which has raised the possibilities for omitting the high-temperature solution treatment step that usually precedes ageing heat treatment for these alloys. In this work, the as-built microstructure of a high gamma prime fraction superalloy Inconel 939 is presented, where the absence of any γ′ precipitation is notable. However, transmission electron microscopy shows the presence of nano-sized Eta (η) phase. It is shown that the omission of solution treatment leads to the growth of the deleterious η phase upon ageing, which results in embrittlement in tensile loading. It is concluded that at least for this particular alloy the solution treatment plays a critical role in the establishment of the required microstructure and hence cannot be omitted from the heat treatment.

A new high strength Al–Mg–Sc alloy for laser powder bed fusion with calcium addition to effectively prevent magnesium evaporation

A precise control of the Mg content in Al–Mg alloys is essential to obtain predictable mechanical properties but the processing of Al–Mg alloys often suffers Mg losses due to Mg evaporation and oxidation. A new high strength Al–Mg–Sc alloy designed for LPBF (laser powder bed fusion) processing has been developed here, where Mg losses are effectively prevented by the addition of a low amount of calcium. A LPBF processing window which results in built parts with a 99.7% relative density and no detectable loss of Mg has been identified. The as-built microstructure of the new Calciscal® alloy, studied by transmission electron microscopy, is found to comprise areas of fine equiaxed grains and areas of coarser grains, with many Al 4 Ca precipitates present at the grain boundaries and within the coarser grains. After a subsequent ageing of 1 h at 375 °C, the tensile strength of Calciscal® is increased by 44% compared to the as-built condition and reaches 522 ± 2 MPa. The increase in strength observed in the heat-treated condition comes from the additional precipitation of numerous finely dispersed Sc-rich precipitates. This high strength, combined with a good ductility, makes Calciscal® competitive to other Al alloys and suitable for structural applications. Moreover, Calciscal® shows very reproducible tensile properties thanks to the Ca addition which leads to a better control and less variations of the Mg content in the alloy.

Multi-layer deposition mechanism in ultra high-frequency pulsed wire arc additive manufacturing (WAAM) of NiTi shape memory alloys

Ultra high-frequency pulsed gas tungsten arc welding (UHFP-GTAW)-based Wire Arc Additive Manufacturing (WAAM) was used to fabricate thin walls of NiTi shape memory alloys. The transient heat and fluid flow are critical during fusion-based additive manufacturing, since they impact the as-built microstructure. In this work, a three-dimensional numerical model, which includes the force, surface Gauss heat source and periodic droplet transfer models, was developed to simulate the deposition of 5 layers. The gravity, buoyancy, electromagnetic, surface tension, arc pressure and arc shear stress are considered in the developed force model. An improved free surface tracing method using the volume of fluid (VOF) technique was proposed to more effectively track the free surface of the molten pool with the computational fluid dynamics (CFD) software FLUENT. The multiphysics phenomena associated to the process, namely the temperature and velocity fields of the molten pool, were studied. The model was then validated by experiments. It is revealed that the microstructure of the as-built parts is refined by the UHFP current power which induces significant vibration of the molten pool. These findings lay the foundations for optimizing the WAAM process aiming at fabricating high quality and complex NiTi parts. • Ultra high-frequency pulsed WAAM is used to promote grain refinement in as-built NiTi parts. • Development of a numerical modeling approach to understand the deposition mechanism and its effect on the molten pool. • The ultra high-frequency current promotes significant vibration of the molten pool thus inducing grain refinement. • Good agreement between experimental and modelling approaches was achieved.

Role of scan strategies and heat treatment on grain structure evolution in Fe-Si soft magnetic alloys made by laser-powder bed fusion

A major goal in printing soft magnetic Fe-Si steels using additive manufacturing is to take advantage of the potential for complex geometric designs and site-specific grain control. One major step in the processing of these alloys is understanding how processing parameters might impact how the as-built microstructure responds to annealing (i.e. the annealing response). The impact of scan strategy on the annealing response for thin wall geometries is specifically explored. Two scan strategies were explored for a thin wall geometry that produced a strongly columnar grain structure and equiaxed grain structure. Samples from both scan strategies annealed at 1200 °C showed a marked difference in annealing response with the more equiaxed sample seeing full recrystallization and grain growth, while the more columnar grain structure saw little change in microstructure. After analysis through characterization techniques and thermal-mechanical simulations Differences in internal energy within the grains were ruled out because calculated GND density values were similar for both samples. The formation of secondary particles was ruled out as a contributing factor due to the type of oxide formations and their size. It was concluded that the contributing factor to the difference in the annealing response were a difference in the resulting grain size and the density of high angle grain boundaries. These two differences were largely attributed to differences in the thermal gradient conditions due to grains preferentially growing in the direction of the steepest thermal gradient. • Different scan strategies result in different microstructures for thin wall samples printed in Soft magnetic Fe-3Si Steel. • Differences in resulting microstructure between samples can be attributed to differences in the resulting thermal gradient. • Annealing of samples show that the sample with a higher number of equiaxed grains saw faster grain growth. • Similar geometric necessary dislocation (GND) densities were noted for the as-built samples but not the annealed samples. • Differences in annealing response is attributed to differences in grain size and density of high angle grain boundaries.

Optimization of the Post-Process Heat Treatment Strategy for a Near-α Titanium Base Alloy Produced by Laser Powder Bed Fusion.

During the last decades, titanium alloys have been of great interest for lightweight applications due to their high strength in combination with a low material density. Current research activities focus on the investigation of near-α titanium alloys produced by laser powder bed fusion (LPBF). These alloys are known for their superior tensile strength and high creep resistance. This study focuses on the optimization of post-process heat treatments and the impact on tensile and creep strength of a LPBF produced Ti6242S alloy. Therefore, a variety of annealing steps were conducted to gain knowledge about the decomposition process of the non-equilibrium as-built microstructure and the arising influence on the mechanical properties. Components made of Ti6242S and produced by LPBF reveal an extraordinarily high ultimate tensile strength of about 1530 MPa at room temperature, but show a low elongation at fracture (A5 = 4.3%). Based on microstructure-property relationships, this study recommends precise heat treatments on how to improve the desired mechanical properties in terms of strength, ductility as well as creep resistance. Moreover, this study shows a triplex heat treatment, which enhances the elongation at fracture (A5) to 16.5%, while the ultimate tensile strength is still at 1100 MPa.

Characterization and statistical modeling of texture and microstructure evolution in dynamically fractured electron beam melted Ti-6Al-4V

Two different Ti-6Al-4V cylindrical rods, horizontally and vertically built, fabricated through the electron beam melting technique, were underwent compression loadings to failure at the strain rates of 2350s−1 and 1750s−1, respectively. Low-angle grain boundary formation, dislocation array, and dislocation pinning were observed and attributed to the stress-induced dislocation formation in the as-built microstructure. Superior strength at each strain rate in vertically built samples was concluded to be a consequence of its finer microstructure and the presence of martensite α˙. Hardness measurements revealed higher values at the areas close to the fracture surface. Electron microscopic characterization revealed parallel-twin formation resulting from adiabatic temperature rise, increasing short-ranged clustering, and the high stacking fault energy. Dynamic compressive deformation led to the appearance of dislocation structure, cell blocks, and extended dislocation walls formation. Texture analysis showed <c+a> type pyramidal slip systems and contraction twins as the most favorable slip systems. Texture evolution interpretations from the region far from the area close to the fractured surface indicated that mean grain size decreased, and higher dislocation densities were obtained. The more preferred texture tended to rotate by approaching the fracture surface so that the basal plane became parallel to the fracture surface, which is directly related to the facilitation of crack propagation. Moreover, the generalized spherical harmonics were used to apply 2-point statistics on the texture and then statistically compare the texture changes. The results were in good agreement statistically, where principal components (PC) were utilized to explain variances in the database.