Texture Intensity Research Articles

Fine Classification of Urban Tree Species Based on UAV-Based RGB Imagery and LiDAR Data

Rapid and accurate classification of urban tree species is crucial for the protection and management of urban ecology. However, tree species classification remains a great challenge because of the high spatial heterogeneity and biodiversity. Addressing this challenge, in this study, unmanned aerial vehicle (UAV)-based high-resolution RGB imagery and LiDAR data were utilized to extract seven types of features, including RGB spectral features, texture features, vegetation indexes, HSV spectral features, HSV texture features, height feature, and intensity feature. Seven experiments involving different feature combinations were conducted to classify 10 dominant tree species in urban areas with a Random Forest classifier. Additionally, Plurality Filling was applied to further enhance the accuracy of the results as a post-processing method. The aim was to explore the potential of UAV-based RGB imagery and LiDAR data for tree species classification in urban areas, as well as evaluate the effectiveness of the post-processing method. The results indicated that, compared to using RGB imagery alone, the integrated LiDAR and RGB data could improve the overall accuracy and the Kappa coefficient by 18.49% and 0.22, respectively. Notably, among the features based on RGB, the HSV and its texture features contribute most to the improvement of accuracy. The overall accuracy and Kappa coefficient of the optimal feature combination could achieve 73.74% and 0.70 with the Random Forest classifier, respectively. Additionally, the Plurality Filling method could increase the overall accuracy by 11.76%, which could reach 85.5%. The results of this study confirm the effectiveness of RGB imagery and LiDAR data for urban tree species classification. Consequently, these results could provide a valuable reference for the precise classification of tree species using UAV remote sensing data in urban areas.

Effect of rotational-die ECAP parameters on microstructure and mechanical properties of Mg97Y2Zn alloys

In this work, the Mg97Y2Zn (at%) alloys have been processed by the rotary-die (RD) ECAP technique under different temperature or pass conditions to tailor the microstructure and mechanical properties. The results reveal that the DRX ratio (VDRX) increases with the increase of ECAP pass or temperature, weakening the texture intensity. The refinement of DRXed grains saturates after 9 passes of ECAP at 350 °C, while the size of DRXed grains (dDRX) monotonically decreases with the reduction of temperature from 400 °C to 300 °C in the case of the same pass number (9P). The combination of fine dDRX, large VDRX, and directionally arranged LPSO phases along the extrusion direction endows the 350 °C–9P alloy with the optimum strength and ductility synergy, exhibiting the tensile yield strength (TYS) of 267 MPa, ultimate tensile strength (UTS) of 318 MPa, and elongation of 10.3%. However, the larger VDRX, weaker texture, less low-angle grain boundaries combine to improve the elongation (14.7%) of the 400 °C–9P alloy at the expense of the TYS (231 MPa) and UTS (303 MPa). This paper provides useful information to optimize the RD-ECAP parameters for the fabrication of high-performance Mg97Y2Zn alloys.

Low-cycle fatigue behaviour of extruded 7075 aluminium alloy bar: Competition of grain sizes and textures

The low-cycle fatigue (LCF) behaviour of a large 7075 aluminium alloy bar was investigated, and the results indicated that the microstructure at the center (0R) and surface section of the bar (R) were different in terms of grain sizes and textures. The microstructure of the 0R specimen was characterised by coarser elongated grain and higher <111> texture intensity compared to that of the R specimen. The LCF life of the 0R specimen was higher than that of the R specimen at a strain amplitude range of 0.6%–0.9%, thereby indicating the dominant effect of higher texture intensity. However, the 0R specimen sustained short LCF life at low strain amplitudes of 0.4% and 0.5%, indicating the predominant effect of grain refinement. The fracture analysis results indicated that there were wider striations for the 0R specimen at a strain amplitude of 0.4%. Interestingly, the yield strength, ultimate tensile strength and elongation of the 0R specimen were higher than that of the R specimen. The higher mechanical properties of the 0R specimen was consistent with its longer low cycle fatigue life at strain amplitude range of 0.6%–0.9%. Moreover, the features of the fracture, including fracture initiation and fast fracture regions, were also elaborated. The competition of grain sizes and texture evolutions determined the LCF life of the alloy depending on the strain amplitude range: the grain size effect gradually overshadowed that of the texture with decreasing strain in terms of fatigue life.

Dosage- and site-dependent retention of black carbon and polycyclic aromatic hydrocarbons in farmland soils via long-term biochar addition

Biochar, a soil conditioner containing significant amounts of polycyclic aromatic hydrocarbons (PAHs), has gained widespread popularity in agricultural practices due to its advantages in improving soil fertility and carbon sequestration. While biochar may increase soil black carbon (BC) and PAH contents, the quantitative accumulation of BC and PAHs in different soil environments under varying biochar addition dosages remains poorly understood. Here, we investigated the content and composition of black carbon (evaluated using benzene polycarboxylic acids, BPCAs) and PAHs in soils treated with different biochar addition dosages from two long-term experimental farmlands in Ningxia (5-year) and Shandong (7- and 11-year), China. Results showed that increasing cumulative biochar dosage caused elevated contents of black carbon and PAHs, accompanied by decreases in their retention efficiencies. Contrasting retention was observed between sites, with the Shandong site characterized by higher retention efficiencies of BPCAs and lower retention efficiencies of PAHs, possibly owing to its higher temperature, more sandy soil texture, less irrigation, and lower sunlight intensity. Despite both black carbon and PAHs originating from biochar and sharing similar condensed aromatic structures, there was no significant correlation between the contents of black carbon and PAHs, indicating distinct behaviors and fates of these compounds. These findings emphasize the importance of optimizing biochar addition dosages and considering site-specific environmental factors for effective soil black carbon sequestration through biochar application.Graphical

Effect of microstructure and texture on directional dependent plastic flow behavior of refractory alloy Nb-10Hf-1Ti

This article investigates the directional dependency of the tensile plastic flow and work-hardening behavior of a cold-rolled plus annealed sheet made of the refractory alloy Nb-10Hf-1Ti. Three tensile test directions such as 0° to the rolling direction (RD) (sample-S0), 45° to the RD (sample-S45), and 90° to RD (sample-S90) have been used in this investigation. When the tensile test is performed along 0° and 90° to RD, both the α- and γ-fibres evolve, and the overall texture intensity decrease while testing in the direction 45° to RD, the starting γ-fibre changes to α-fibre and the overall texture intensity remains unchanged. The lowest value of the Schmid factor of the primary slip system in the presence of (111) [01‾1] texture component of γ-fibre results in the highest value of yield strength of sample S90 as compared to samples S0 and S45. The presence of texture components (111) [11‾0] and (111) [01‾1] of γ-fibre strongly influences the deformation mechanism of the S90 sample by lowering the Schmid factor of slip systems resulting in grain fragmentation and lower value of strain to fracture. The plastic flow curves of the tensile deformed samples in all three directions follow the Ludwigson relationship. The work-hardening rate of the alloy Nb-10Hf-1Ti displays its directional dependence and is well explained by the Kock-Mecking-Estrin analysis.

Texture Intensity in Grain-Oriented Steel in the Main Stages of the Production Cycle

Grain-oriented electrical steel (GOES) has been used for many years for application in transformed cores due to its excellent magnetic properties. Magnetic properties are strongly influenced by obtaining a texture with a certain orientation (110) [001] for BCC structure. This is related to the easy direction of magnetization [001]. So far, the main research has been focused on obtaining a strong texture in the last stages of the process. The aim of the present study was to additionally trace textural changes for a slab after the continuous casting (CC) process and for a sheet after the hot rolling process. The scope of such an analysis has not been conducted before. With regard to the state after continuous casting (CC), the texture was related to measurements of the anisotropy of Barkhausen magnetic noises and the macrostructure of the slab. Based on the X-ray diffraction examinations that compared the texture intensity calculated from the texture coefficient of the slab, the hot rolled steel and the final product of grain-oriented electrical steel contained 3.1% of Si. The studies performed with the material taken from three different production steps showed high differences in the values of textural intensity indicating the occurrence of a crystallization texture, especially in the area of the columnar crystal zone; textural weakness after the hot rolling process and high texturing in the final product for textural components corresponding to the desired Goss texture.

“Soft-hard” microstructure evolution and its relevance to high strength–plasticity and low plastic anisotropy of Al–Mg alloys based on ultra-fast heating

The mechanical anisotropy caused by the apparent texture after large plastic deformation and deformation strengthening in metals has always been a contradiction. Here, 80 % cold-rolled Al–Mg alloy was annealed using the ultra-fast heating process (500 °C/s heating to 450 °C), leading to substructured grains with high geometrically necessary dislocations (4.12 × 1014 m−2) and recrystallized grains with low geometrically necessary dislocations (0.78 × 1014 m−2); each of these accounted for approximately 50 % of the grains. The alloy's strength was much higher than the corresponding conventional annealing one, while the ductility remained unchanged. In addition, the weaker transition texture components such as Brass, Z, R-GossND, and Goss increased significantly due to the presence of many substructural grains. In contrast, the Cube texture decreased significantly, thus leading to a decrease in the texture intensity and, in turn, a significant reduction in the anisotropy. The excellent comprehensive properties are attributed to the microstructures with a mixture of “soft-hard” grains and multicomponent-low-intensity textures. The present study provides a new approach to fabricating Al–Mg alloys with high strength, high ductility, and a low anisotropy of the mechanical properties.

Cold Formability of Twin-Roll Cast, Rolled and Annealed Mg Strips

This study investigates the cold formability of twin-roll cast and rolled magnesium strips, specifically focusing on AZ31 and ZAX210 alloys. The aim is to assess the suitability of these alloys for various forming processes. The mechanical properties and formability characteristics of the strips were thoroughly examined to provide insights into their potential applications in transportation industries such as automotive and aerospace. The AZ31 and ZAX210 alloys were subjected to twin-roll casting and rolling processes to produce thin strips. The resulting strips were then evaluated for their cold formability. The results indicate that both alloys exhibit favourable cold formability. The ZAX210 alloy, in particular, demonstrates medium strengths with an average tensile strength of approximately 240 MPa at room temperature. The 0.2% proof stress values range between 136 MPa and 159 MPa, depending on the sampling direction. The total elongation values vary from 28% in the transverse direction to 32% at a 45° angle, indicating excellent ductility. Comparing the two alloys, the AZ31 alloy shows higher strengths due to its higher aluminium content. However, it also exhibits a more pronounced directional dependence of mechanical properties due to the formation of a strong basal texture during hot rolling. The transverse direction experiences reduced total elongation compared to the rolling direction, achieving only about 50% of the total elongation. The average Erichsen Index recorded for AZ31 and ZAX210 strips were 4.9 mm and 7.1 mm, respectively. The ZAX210 strip displays superior formability, which can be attributed to the fine-grained microstructure and the texture softening resulting from the weakening of the basal texture intensity and the splitting of the basal pole towards the rolling direction. In conclusion, the investigated twin-roll cast, rolled and annealed AZ31 and ZAX210 magnesium strips exhibit promising cold formability characteristics. The findings of this study contribute to the understanding of their mechanical behaviour and can guide the selection and optimisation of these alloys for various forming applications.

High-temperature compression deformation strengthening mechanism of Mg–Gd–Y–Zn–Zr alloy formed by cold metal transfer (CMT) arc additive forming

The Mg–Gd–Y–Zn–Zr alloy structural parts were formed by CMT arc additive forming. The high-temperature compression deformation strengthening mechanism of the alloy at 623–723 K, 0.01–1s−1, and 50 % deformation was studied. Upon a decrease in the temperature or an increase in the strain rate, the effect of fine-grain strengthening was obvious, which led to the improvement of the mechanical properties of the alloy after deformation. The grain refinement was mainly attributed to the DDRX and CDRX processes during hot deformation. Because the compression specimen was loaded along the building direction, the twins after deformation were compression twins {10–11}, and the content increased with an increase in the strain rate or a decrease in the temperature. As the strain rate increased, the texture distribution on the {10-10} plane became more concentrated and the texture intensity decreased from 6.79 to 2.24. This was attributed to the fact that the alloy was mainly dominated by a non-basal slip during high-temperature deformation, which increased the sensitivity of the strain rate to the texture.

CALPHAD-linked analysis of grain boundary segregation and phase-field simulation of solute-drag effect in multicomponent magnesium alloys

The application of Mg alloy sheets is currently limited owing to their poor room-temperature formability. The solute-drag effect is a potential mechanism via which the texture intensity of Mg alloys can be lowered to improve their formability. However, detailed analyses of the effects of solute–solute interactions on the solute drag in multicomponent systems are lacking. Herein, a CALPHAD-linked phase-field model was developed to evaluate the grain boundary segregation and solute-drag effects in a multicomponent system. The model was used to calculate the grain boundary segregation and solute drag in several Mg alloys, and the effect of solute–solute interactions on these phenomena was evaluated. The results showed that Zn and Ca mutually enhanced the grain boundary segregation in Mg alloys, leading to greater solute drag. However, the combination of Al and Zn mutually suppressed the grain boundary segregation and consequently, reduced the solute drag. These results support a previously proposed theory that Mg-Zn-Ca alloys exhibit strong solute drag owing to the co-addition of Zn and Ca, which reduces the texture intensity and improves the room-temperature formability. Furthermore, a new index for describing co-segregation and competitive segregation at grain boundaries, based on Hillert's grain boundary phase model, was introduced. The value of the index was calculated for various combinations of alloying elements in Mg alloys. The results showed that many ternary Mg alloys with a low texture intensity tended to co-segregate alloying elements.

Unveiling the microstructure evolution and deformation mechanisms of micro-alloying Mg-1.5Zn-0.5Zr-0.5Sr alloy via extrusion-shearing

Obtaining high strength without sacrificing ductility in Mg alloys is of great importance. However, the hexagonal close-packed crystal structure critically limits the deformation of Mg alloys. In this work, novel Mg-1.5Zn-0.5Zr-0.5Sr (wt.%) alloys were fabricated through homogenization, direct extrusion (DE), and extrusion-shearing (ES) processes. The effects of three different processes on microstructures, texture, and mechanical properties were thoroughly investigated. The results show that the average grain size of the alloy was greatly refined after hot extrusion. The alloy after the DE process exhibited a typical bimodal microstructure with dynamic recrystallized (DRXed) grains showing a strong <101‾0 > fiber texture parallel to extrusion direction (ED), while the small-sized unDRXed grains showed relatively weak basal texture. In addition, the strength was significantly improved, with the value of yield strength (YS) reaching ∼229 MPa and ultimate tensile strength (UTS) reaching ∼262 MPa. This is mainly attributed to grain boundary strengthening and dislocation strengthening. Compared to the DE-processed alloy, the basal texture intensity was significantly decreased and non-basal slip was activated after the ES process, which indicates that the shearing deformation during ES could improve the ductility, with the fracture elongation (FE) increased from ∼13.9 % to ∼21.4 %. This work aims to unveil the deformation mechanisms in Mg-1.5Zn-0.5Zr-0.5Sr alloy and provides an efficient way for preparing micro-alloying Mg alloys with low cost and significant improvement of comprehensive properties.

Weld appearance, microstructure evolution and microhardness of welded joint in the TC4 additive manufactured component TIG welding

In this work, TC4 titanium alloy CMT additive thin-walled components is selected as base metal to study the weld formation, microstructure evolution, and microhardness of TIG welded joint. The results showed that the thin-walled components could obtain a good formation after TIG welding. The weld seam was mainly consisted of equiaxed and columnar of β grain. The maximum texture intensity of β phase in the weld surface was only 10.746. Therefore, there was no obvious preferred growth direction in the weld seam. The heat affected bands (HAB) in the zone of weld seam was disappeared due to the base metal no undergone multiple heating cycles after melting. In the weld cross-section and weld surface, the average hardness of base metal is about 334.5 HV and 358.8 HV, respectively. The hardness of weld seam was greater than that of the base metal. The hardness of weld surface was greater than that of weld cross-section. The change of hardness of welded joint was mainly caused by β grain size and α phase.

Twinning-assisted static recrystallization and texture evolution in a Mg-Gd-Y-Zr alloy

The formability and mechanical properties of magnesium (Mg) alloys are strongly related to the crystallographic basal texture. Twins play critical roles in adjusting crystallographic orientation of grains during both deformation and annealing treatment via deformation twinning and twinning-assisted recrystallization. In this study, cold rolling and subsequent annealing were conducted on a Mg-5.9Gd-3.3Y-0.5Zr alloy to investigate the recrystallization behavior and texture evolution. Electron backscatter diffraction and transmission electron microscopy techniques were applied to characterize the nucleation of recrystallized grains, especially the twinning-assisted recrystallization, at multi-scales. The results indicated that a large number of {101‾2}, {101‾1} twins and {101‾1}‐{101‾2} double twins were introduced after cold rolling. The {101‾1}‐{101‾2} double twins, double twin - grain boundary intersections and dense twin-twin intersections acted as the preferential nucleation sites for recrystallization during annealing treatment, while the coarse and parallel {101‾2} twins were unfavorable for the nucleation of recrystallized grains. Although {101‾2} tension twins are the most common twins in Mg alloys, the interface of this type of twin has strong mobility and is easy to expand. Therefore, it is generally difficult for a single {101‾2} twin to recrystallize. However, the {101‾1} compression twins and {101‾1}‐{101‾2} double twins are generally difficult to expand and can store high deformation energy, so they are conducive to becoming nucleation sites for recrystallization. During the recrystallization process, the texture type (basal texture) of the cold rolled sample remained unchanged, but the overall texture intensity was significantly reduced due to the dispersion of grain orientations brought by new grains generated by twinning recrystallization.

Deformation behavior of LPSO phases, grain refinement mechanism, and texture evolution of a Mg-Gd-Y-Zn-Zr alloy processed by forward extrusion combined with dual-directional angular deformation

In this study, a Mg-Gd-Y-Zn-Zr alloy was processed by forward extrusion combined with dual-directional angular extrusion (FE-DDAE), and the corresponding microstructure evolution, grain refinement mechanism, and texture were investigated systematically. The deformed materials were subjected to a combination of three-way compressive stress and shear stress, and five different areas were selected to study the typical deformation behaviors. The results show that microstructures are heterogeneous in different areas, and the grain size is refined from 138.70 μm to 37.18 μm through continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The block-shaped and lamellar long period stacking ordered (LPSO) phases can coordinate severe deformation through dissolution, tearing, breaking for the former, and bending, severe kinking, refining into small pieces for the latter. Moreover, the broken block-shaped LPSO can promote DRX process through particle-stimulated nucleation (PSN) mechanism, and the lamellar LPSO phases can hinder the dislocation motion to restrict DRX. A strong basal texture is observed during the initial stage of FE-DDAE process, and the basal texture intensity gradually weakens to 4.9 MRD due to the random orientations of high volume fraction of DRX grains. A mixed texture component is formed with basal planes inclined 50° from ED to TD, showing a trend of spreading.

Investigating the microstructure and mechanical behavior of optimized eutectic Al[sbnd]Si alloy developed by direct energy deposition

Wire arc additive manufacturing (WAAM) is a direct energy deposition process majorly used to fabricate large and medium-sized components. However, the process encounters defects, such as anisotropic microstructure and mechanical properties, residual stresses, excessive oxidation, and geometrical irregularities. Hence, efforts have been made to address the issues by optimizing the process parameters and incorporating in situ and post-process treatment to improve mechanical properties. In line with this, the present work deals with statistical-based process parameter optimization based on a multicriteria approach. The responses were quantified, statistically analyzed, and correlated with the process parameters. Travel speed exhibited a minor effect on all responses, while the current and wire feed speed significantly affected the responses. The percentage porosity was more sensitive to welding current than the other parameters. The maximum ultimate tensile strength (UTS) of 193.73 ± 3.93 MPa and yield strength (YS) of 108.09 ± 12.28 were displayed by Wall 2. YS and UTS showed marginal variation in vertical and horizontal directions, while % elongation showed significant variation. The desirability Wall (DW) exhibits better-forming quality due to the minimization of the contact angle, and fibrous silicon was observed between the layers. In contrast, it appears to be fragmented silicon at the interfacial region due to remelting and breakdown of Si. However, there were a few limitations to the DW wall's mechanical properties due to coarser dendrites and bulk eutectic at the interface. The average grain size of the bottom and top region for the optimized parameter is 111.156 μm and 173.66 μm, respectively. The observed texture components in the top region include C{001} 〈110〉, A2* (111) [112¯], A (11¯1) [110], and B (11¯2) [110], exhibiting a maximum texture intensity of 10.414. In the bottom region, the identified texture components are B¯ (1¯12¯) [1¯1¯0], B (11¯2) [110], A (11¯1) [110], C{001} <110> with a maximum texture intensity of 10.110.

Creep behaviors of Mg–6Zn-0.4Mn-0.3Al-0.2Ca (wt.%) alloy enhanced by icosahedral quasicrystal

Magnesium (Mg) alloys are considered to be the lightest metal structural materials, however, their poor creep resistance considerably limits their applications. In this study, a novel Mg–6Zn-0.4Mn-0.3Al-0.2Ca (ZMAX6000) alloy with icosahedral quasicrystal phases (I-phases) distributed at almost all triangular grain boundaries was developed by hot extrusion and heat treatment. Tensile creep tests were systematically conducted on the alloy at temperatures of 398 K, 423 K, and 448 K under stresses of 50 MPa, 70 MPa, and 90 MPa, respectively. These I-phases could reduce the accumulation of creep damage at triangular grain boundaries, hinder grain boundary sliding, and delay the generation of cracks. As a result, the ZMAX6000 alloy exhibited far superior creep properties compared to ZK60 and AZ91 alloys. During the creep process, non-basal slip occurred and the texture intensity of the sample was weakened. Dislocation characterization results showed that the creep mechanisms of the alloy at 448 K under 90 MPa were cross-slip and pyramidal < c + a > slip.

Identification of Comprehensive Biomarkers in Patients With Mismatch Repair-Deficient Colon Adenocarcinoma Based on Parallel Multiomics

Immunocheckpoint inhibitors have shown impressive efficacy in patients with colon cancer and other types of solid tumor that are mismatch repair-deficient (dMMR). Currently, PCR-capillary electrophoresis is one of the mainstream detection methods for dMMR, but its accuracy is still limited by germline mismatch repair (MMR) mutations, the functional redundancy of the MMR system, and abnormal methylation of MutL Homolog 1 promoter. Therefore, this study aimed to develop new biomarkers for dMMR based on artificial intelligence (AI) and pathologic images, which may help to improve the detection accuracy. To screen for the differential expression genes (DEGs) in dMMR patients and validate their diagnostic and prognostic efficiency, we used the expression profile data from the Cancer Genome Atlas (TCGA). The results showed that the expression of Immunoglobulin Lambda Joining 3 in dMMR patients was significantly downregulated and negatively correlated with the prognosis. Meanwhile, our diagnostic models based on pathologic image features showed good performance with area under the curves (AUCs) of 0.73, 0.86, and 0.81 in the training, test, and external validation sets (Jiangsu Traditional Chinese Medicine Hospital cohort). Based on gene expression and pathologic characteristics, we developed an effective prognosis model for dMMR patients through multiple Cox regression analysis (with AUC values of 0.88, 0.89, and 0.88 at 1-, 3-, and 5-year intervals, respectively). In conclusion, our results showed that Immunoglobulin Lambda Joining 3 and nucleus shape–related parameters (such as nuclear texture, nuclear eccentricity, nuclear size, and nuclear pixel intensity) were independent diagnostic and prognostic factors, suggesting that they could be used as new biomarkers for dMMR patients.

Influence of solution heating rate on grain structures and fatigue crack propagation behaviors of an aviation Al-Li alloy sheet

In this study, the effects of grain structure on the fatigue crack propagation (FCP) behaviors in the aviation Al-Li alloy sheets prepared by varying solution heating rates are discussed systematically. The results reveal that both the intensity of Goss texture and grain dimensions are improved with the decreased solution heating rates. Upon an identical stress intensity factor range (ΔK), the increased Goss texture of the sample with a solution heating rate of 2 ℃/min (2HR) promotes crack deflection, causing a decrease in FCP rates compared to that of the sample with a solution heating rate of about 100 ℃/min (FHR). The dislocations clustered near grain boundaries are more significant with increasing grain size during cyclic loading, which intensifies the strain localization. The accumulation of dislocations increases the possibility of micro-voids formation and creates the conditions for crack deflection, which results in a decrease in FCP rate. Besides, based on the calculation of the reversible plastic zone (RPZ) size, the initial ΔK entering the rapid propagation region increases with decreasing solution heating rates and exhibits a strong linear relationship with grain size.

Dynamic Compressive Properties and Failure Mechanism of the Laser Powder Bed Fusion of Submicro-LaB6 Reinforced Ti-Based Composites.

In this study, lanthanum hexaboride (LaB6) particle-reinforced titanium matrix composites (PRTMCs, TC4/LaB6) were successfully manufactured using the laser powder bed fusion (LPBF) process. Thereafter, the effect of the mass fraction of LaB6 on the microstructure and the dynamic compressive properties was investigated. The results show that the addition of LaB6 leads to significant grain refinement. Moreover, the general trend of grain size reveals a concave bend as the fraction increases from 0.2% to 1.0%. Furthermore, the texture intensity of prior β grains and α grains was found to be weakened in the composites. It was also observed that the TC4/LaB6 have higher quasi-static and dynamic compressive strengths but lower fracture strain when compared with the as-built TC4. The sample with 0.5 wt.% LaB6 was found to have the best strength-toughness synergy among the three groups of composites due to having the smallest grain size. Furthermore, the fracture mode of TC4/LaB6 was found to change from the fracture under the combined action of brittle and ductility to the cleavage fracture. This study was able to provide a theoretical basis for an in-depth understanding of the compressive properties of additive manufacturing of PRTMCs under high-speed loading conditions.

Effect of Heating Rate on the Annealing Behavior of Aluminium Alloys

This contribution presents a study on the effect of heating rate maintained during annealing treatment on the final microstructure and mechanical properties of cold rolled Al1050 sheet. This study is focused on microstructure and texture evolution of Al1050 annealed at various heating rates, annealing temperatures, and holding times. It was observed that the longer exposure time for deformed microstructure affects the Vickers hardness values, grain size, and texture intensity. It seems that the crystallographic texture evolution is not affected by heating rate on quantitative level since the same set of orientations tended to evolve in all studied cases. The sample annealed at slow heating rate in a box-type furnace produced recrystallized microstructure with fine grain size, and comparatively lower texture intensity &amp; hardness.