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(Ti8Zr6Nb4V5Cr4)100−xAlx(x= 0, 0.1, 0.2, 0.3, 0.4 at.%) lightweight high-entropy alloys with different contents of Al were prepared via vacuum non-consumable arc melting method. Effects of adding varying Al contents on phase constitution, microstructure characteristics and mechanical properties of the lightweight alloys were studied. Results show that Ti8Zr6Nb4V5Cr4alloy is composed of body-centered cubic (BCC) phase and C15 Laves phase, while (Ti8Zr6Nb4V5Cr4)100−xAlxlightweight high-entropy alloys by addition of Al are composed of BCC phase and C14 Laves phase. Addition of Al into Ti8Zr6Nb4V5Cr4lightweight high-entropy alloy can transform C15 Laves phase to C14 Laves phase. With further addition of Al, BCC phase of alloys is significantly refined, and the volume fraction of C14 Laves phase is raised obviously. Meanwhile, the dimension of BCC phase in the alloy by addition of 0.3 at.% Al is the most refined and that of Laves phase is also obviously refined. Adding Al to Ti8Zr6Nb4V5Cr4alloy can not only reduce the density of (Ti8Zr6Nb4V5Cr4)100−xAlxalloy, but also improve strength of (Ti8Zr6Nb4V5Cr4)100−xAlxalloy. As Al content increased from 0 to 0.4 at.%, the density of the alloy decreased from 6.22 ± 0.875 to 5.79 ± 0.679 g cm−3. Moreover, compressive strength of the alloy by 0.3 at.% Al addition is the highest to 1996.9 MPa, while fracture strain of the alloy is 16.82%. Strength improvement of alloys mainly results from microstructure refinement and precipitation of C14 Laves by Al addition into Ti8Zr6Nb4V5Cr4lightweight high-entropy alloy.

The intelligent detection technology driven by X-ray images and deep learning represents the forefront of advanced techniques and development trends in flaw detection and automated evaluation of light alloy castings. However, the efficacy of deep learning models hinges upon a substantial abundance of flaw samples. The existing research on X-ray image augmentation for flaw detection suffers from shortcomings such as poor diversity of flaw samples and low reliability of quality evaluation. To this end, a novel approach was put forward, which involves the creation of the Interpolation-Deep Convolutional Generative Adversarial Network (I-DCGAN) for flaw detection image generation and a comprehensive evaluation algorithm named TOPSIS-IFP. I-DCGAN enables the generation of high-resolution, diverse simulated images with multiple appearances, achieving an improvement in sample diversity and quality while maintaining a relatively lower computational complexity. TOPSIS-IFP facilitates multi-dimensional quality evaluation, including aspects such as diversity, authenticity, image distribution difference, and image distortion degree. The results indicate that the X-ray radiographic images of magnesium and aluminum alloy castings achieve optimal performance when trained up to the 800th and 600th epochs, respectively. The TOPSIS-IFP value reaches 78.7% and 73.8% similarity to the ideal solution, respectively. Compared to single index evaluation, the TOPSIS-IFP algorithm achieves higher-quality simulated images at the optimal training epoch. This approach successfully mitigates the issue of unreliable quality associated with single index evaluation. The image generation and comprehensive quality evaluation method developed in this paper provides a novel approach for image augmentation in flaw recognition, holding significant importance for enhancing the robustness of subsequent flaw recognition networks.

Refractory high-entropy alloys are considered as potential structural materials for elevated temperature applications. To obtain refractory high-entropy alloys with high strength, different amounts of Si were added into the NbMoTiVW refractory high-entropy alloys. The effects of Si on the phase constitution, microstructure characteristics and mechanical properties of NbMoTiVWSixalloys were investigated. Results show that when the addition of Si is 0, 0.025 and 0.05 (molar ratio), the alloys are consisted of primary BCC and secondary BCC in the intergranular area. When the addition of Si is increased to 0.075 and 0.1, eutectic structure including silicide phase and secondary BCC phase is formed. The primary BCC phase shows dendritic morphology, and is refined by adding Si. The volume fraction of intergranular area is increased from 12.22% to 18.13% when the addition of Si increases from 0 to 0.1. The ultimate compressive strength of the NbMoTiVW alloy is improved from 2,242 MPa to 2,532 MPa. Its yield strength is also improved by the addition of Si, and the yield strength of NbMoTiVWSi0.1reaches maximum of 2,298 MPa. However, the fracture strain of the alloy is decreased from 15.31% to 12.02%. The fracture mechanism of the alloys is changed from mixed fracture of ductile and quasi-cleavage to cleavage fracture with increasing of Si. The strengthening of alloys is attributed to the refinement of primary BCC phase, volume fraction increment of secondary BCC phase, and formation of eutectic structure by addition of Si.

The effects of Ag, Co, and Ge additions on microstructure and mechanical properties of Be-35Al (wt.%) alloys fabricated by investment casting were studied. The results reveal that the trace metals 1.5wt.% Ag, 0.7wt.% Co, and 0.8wt.% Ge additions do not change the nucleation temperature of Be phase. However, the nucleation temperature of the Al phase decreases from 642 °C to 630 °C by DSC due to the Ge addition. The strength of the alloys sharply increases due to the dissolution of the Ag and Ge solutes into the Al phase and the Co into the Be phase characterized by SEM and EDS. Obviously, the strength of Be-Al-Ag-Co-Ge alloy is improved by the solution strengthening. Furthermore, a few Ag3Al particles contribute to the strength of the Al phase. Be-Fe-Al ternary intermetallic compounds which can effectively reduce the negative effect of an impurity element Fe on the mechanical properties of Be-Al alloys are also found by XRD and EDS.

No-bake resin-bonded sand is commonly used in casting production. However, its air pollution is relatively serious, especially in the molding and pouring process. For this reason, it is necessary to study the gas evolution characteristics of no-bake resin-bonded sand from room temperature to high temperatures, and not only the amount of gaseous products, but also the composition of the gaseous products. No-bake furan resin-bonded sand (#1), phenolic urethane no-bake resin-bonded sand (#2), and alkaline phenolic no-bake resin-bonded sand (#3) are the three most common no-bake resin-bonded sands in casting. The gas evolution volume and rate of these three no-bake resin-bonded sands were studied. Thermogravimetry-mass spectrometer (TG-MS), headspace-gas chromatography/mass spectrometer (HS-GC/MS), and pyrolysis-gas chromatography/mass spectrometer (PY-GC/MS) were used to measure the composition of the gaseous products emitted from binders at room temperature and high temperatures. The differences between formaldehyde, heterocyclic aromatic compounds (HAC), monocyclic aromatic hydrocarbons (MAH), and polycyclic aromatic hydrocarbons (PAHs) gaseous products from the three types of no-bake resin-bonded sands during the molding and casting process were compared. From the perspective of environmental protection, alkaline phenolic no-bake resin-bonded sand and no-bake furan resin-bonded sand are better than phenolic urethane no-bake resin-bonded sand.

The healing behavior of shrinkage cavity inside the cast Ti6Al4V alloy during hot isostatic pressing (HIP) was investigated experimentally by interrupted hot isostatic pressing tests. The X-ray micro computed tomography was used to record the morphology changes before and after hot isostatic pressing. The two-dimensional geometry obtained by the microCT scan was used in simulation to study the evolution of the real shrinkage cavity during hot isostatic pressing. Shrinkage cavities, shrinkage porosity and small gas pores can be effectively eliminated under proper HIP conditions. The two-dimensional morphology in the simulation results agrees well with the experimental results. This study reveals that plastic deformation, creep and diffusion are the main mechanisms of cavity closure during hot isostatic pressing. In addition, the simplified elliptical pores with aspect ratios at different positions were used to replace the real pores to further study the factors affecting the position of dimples after HIP by simulation. It is found that the position of the dimples mainly depends on the aspect ratio of the elliptical pore and the distance between the pore surface and the external surface of the geometric model.

Selective laser melting (SLM) has been widely used in the fields of aviation, aerospace and die manufacturing due to its ability to produce metal components with arbitrarily complex shapes. However, the instability of SLM process often leads to quality fluctuation of the formed component, which hinders the further development and application of SLM. In situ quality control during SLM process is an effective solution to the quality fluctuation of formed components. However, the basic premise of feedback control during SLM process is the rapid and accurate diagnosis of the quality. Therefore, an in situ monitoring method of SLM process, which provides quality diagnosis information for feedback control, became one of the research hotspots in this field in recent years. In this paper, the research progress of in situ monitoring during SLM process based on images is reviewed. Firstly, the significance of in situ monitoring during SLM process is analyzed. Then, the image information source of SLM process, the image acquisition systems for different detection objects (the molten pool region, the scanned layer and the powder spread layer) and the methods of the image information analysis, detection and recognition are reviewed and analyzed. Through review and analysis, it is found that the existing image analysis and detection methods during SLM process are mainly based on traditional image processing methods combined with traditional machine learning models. Finally, the main development direction of in situ monitoring during SLM process is proposed by combining with the frontier technology of image-based computer vision.

Additive manufacturing is expected to transform and upgrade the traditional foundry industry to realize the integrated manufacturing and rapid and low-cost development of high-performance components with complex shapes. The additive manufacturing technology commonly applied in casting mold preparation (fusible molds, sand molds/cores and ceramic cores) mainly includes selective laser sintering (SLS) and binder injection three-dimensional printing (3DP). In this work, the research status of SLS/3DP-casting processes on material preparation, equipment development, process optimization, simulation and application cases in aerospace, automotive and other fields were elaborated. Finally, the developing trends of the additive manufacturing technology in the future of foundry field are introduced, including multi-material sand molds (metal core included), ceramic core-shell integration and die-casting dies with conformal cooling runners.

Experiments were carried out to observe the variation in microstructure and mechanical properties of gray cast iron by adding pearlite promoting alloying elements such as Ti, Sn and W. Results show that adding Sn, Ti, and W with different concentrations improve the microstructure, Brinell hardness and tensile strength of gray cast iron. With the increase of alloying element concentration, the average graphite length and graphite content increase linearly. At the same time, average cell size and the maximum graphite length also decrease linearly. Brinell hardness and tensile strength of gray cast iron also increase with an increase in alloying elements contents, and attain the maximum when Ti = 0.561%, Sn = 0.561% and W = 0.945%. However, at higher concentrations of Ti = 0.810%, Sn = 0.631% and W = 1.351%, the tensile strength decreases from 333 MPa to 297 MPa and the Brinell hardness decreases from 248 HB to 225 HB. The decrease in tensile strength and Brinell hardness at the higher concentration level is attributed to the formation of coarse and thick graphite flakes.

High-quality solidification microstructure during directional solidification relies on precise temperature gradient control, so accurate calculation of the temperature field is critical. In this study, a 3D transient global heat transfer model of directional solidification by the Bridgman method based on the finite difference method is developed. The radiation heat in this model is calculated by the discrete transfer method, and a modified method of external surface area for irregular geometric models is proposed to reduce the zigzag shape caused by finite difference grids. Considering the radiative heat transfer between any surface elements of all materials in the directional solidification furnace, a dynamic ray tracing algorithm is developed to simulate the entire process of directional solidification. Then, the simulated results are compared with the theoretical results and experimental results, respectively. Finally, based on the present model and method, the simulation program developed is applied to the directional solidification of actual castings. The simulated results are in good agreement with the experimental results, which indicate that the model and method developed in this study is effective and practical.

The pyrolysis behaviors of foam patterns have critical influences on fluid morphology and defect formation in Lost Foam Casting (LFC). The pyrolysis behaviors of expanded polystyrene (EPS) and styrenemethyl methacrylate (St-MMA) foams were compared using synchronous thermal analysis (STA), which was performed under argon atmosphere at different heating rates (from 10 to 40 K•min-1). The degradation heat was calculated by integrating DSC curves. Results show that the calculated degradation heat of St-MMA (605.28 J•g-1) was significantly lower than that of EPS (706.71 J•g-1). Furthermore, the non-isothermal iso-conversional method was used to determine the pyrolysis apparent activation energies of EPS and St-MMA, and results show that the activation energy of St-MMA (200.36 kJ•mol-1) was apparently higher than that of EPS (167.92 kJ•mol-1). These calculated results indicate that the weight loss rate of EPS is greater than St-MMA in the pyrolysis process. In addition, the apparent activation energies at various pyrolysis stages demonstrate that the pyrolysis reactions of EPS and St-MMA may involve physical and chemical changes in the decomposition layer of the LFC process.

Casting microstructure evolution is difficult to describe quantitatively by only a separate simulation of dendrite scale or grain scale, and the numerical simulation of these two scales is difficult to render compatible. A three-dimensional cellular automaton model couplling both dendritic scale and grain scale is developed to simulate the microstructure evolution of the nickel-based single crystal superalloy DD406. Besides, a macro–mesoscopic/microscopic coupling solution algorithm is proposed to improve computational efficiency. The simulation results of dendrite growth and grain growth of the alloy are obtained and compared with the results given in previous reports. The results show that the primary dendritic arm spacing and secondary dendritic arm spacing of the dendritic growth are consistent with the theoretical and experimental results. The mesoscopic grain simulation can be used to obtain results similar to those of microscopic dendrites simulation. It is indicated that the developed model is feasible and effective.

Selective laser melting (SLM) is a promising technique for additive manufacturing. During SLM of metallic powder, the temperature field and thermal history are important to understand physical phenomena involved. The purpose of this study is to simulate the temperature field during the SLM process of a hollow cylinder shape part based on a fully threaded tree (FTT) technique, and to analyze the temperature variation with time in different regions of the part. A revised model for temperature field simulation in the SLM process was employed, which includes the transition of powder-to-dense sub-model and a moving volumetric Gaussian distribution heat source sub-model. The FTT technique is then adopted as an adaptive mesh strategy in the simulation. The simulation result shows that during the SLM process of cylinder part, the temperature of inner powder bed is obviously higher than external one. The temperature at the internal of the molten pool is also higher than external, which may lead to differences in microstructures and other properties between the two regions.

The Ti6Al4V alloy castings were produced by the investment casting process, and the hot isostatic pressing (HIP) was used to remove shrinkage from castings. The processing pressure and holding time for HIP were 150 MPa and 20 min, respectively. Four different HIP temperatures were tested, including 750 ºC, 850 ºC, 920 ºC and 950 ºC. To evaluate the effects of temperature on densification and microstructure of Ti6Al4V alloy treated by HIP, non-destructive testing and metallographic observation was performed. The experimental results show that the shrinkage was completely closed at 920 ºC and 950 ºC. The densification of Ti6Al4V alloy increased as the HIP temperature increased below 920 ºC. The lamellae were more uniform, the thickness of lamellae was obviously broadened and the structure was coarsen. Besides, the Norton creep equation was used to simulate the effect of different temperatures on the densification of Ti6Al4V alloy during HIP. The simulation results were in good agreement with the experimental results. It was also found that 920 ºC is a suitable temperature for HIP for Ti6Al4V alloy.

In this present work, a multi-phase field model was used to simulate the eutectoid transformation process, and on the basis of the nucleation model that was previously proposed by our research team, anisotropic and orientation relationship models were introduced to study the growth mechanism of the pearlite lamellae with anisotropy. It was found that the growth direction of the pearlite lamellae is related to its orientation and spacing. In the process of lamellar growth, deflection growth of pearlite will appear along with the adjustment of lamellar spacing, and the deflection angle is equal to the orientation difference between the austenite and the pearlite. Comparison between experimental and numerical results indicates a good consistency in pearlite morphology.

The traditional foundry industry has developed rapidly in recently years due to advancements in computer technology. Modifying and designing the feeding system has become more convenient with the help of the casting software, InteCAST. A common method of designing a feeding system is to first design the initial systems, run simulations with casting software, analyze the feedback, and then redesign. In this work, genetic, fruit fly, and interior point optimizer (IPOPT) algorithms were introduced to guide the optimal riser design for the feeding system. The results calculated by the three optimal algorithms indicate that the riser volume has a weak relationship with the modulus constraint; while it has a close relationship with the volume constraint. Based on the convergence rate, the fruit fly algorithm was obviously faster than the genetic algorithm. The optimized riser was also applied during casting, and was simulated using InteCAST. The numerical simulation results reveal that with the same riser volume, the riser optimized by the genetic and fruit fly algorithms has a similar improvement on casting shrinkage. The IPOPT algorithm has the advantage of causing the smallest shrinkage porosities, compared to those of the genetic and fruit fly algorithms, which were almost the same.

The trial-and-error method is widely used for the current optimization of the steel casting feeding system, which is highly random, subjective and thus inefficient. In the present work, both the theoretical and the experimental research on the modeling and optimization methods of the process are studied. An approximate alternative model is established based on the Back Propagation (BP) neural network and experimental design. The process parameters of the feeding system are taken as the input, the volumes of shrinkage cavities and porosities calculated by simulation are simultaneously taken as the output. Thus, a mathematical model is established by the BP neural network to combine the input variables with the output response. Then, this model is optimized by the nonlinear optimization function of the genetic algorithm. Finally, a feeding system optimization of a steel traveling wheel is conducted. No shrinkage cavities and porosities are induced through the optimization. Compared to the initial design scheme, the process yield is increased by 4.1% and the volume of the riser is decreased by 5.48×106mm3.

The article analysis and summary how to control the final pressure value of site operation by taking project in Changchun as an example when the cohesive soil layer use static prestressed concrete pipe pile foundation, putting forward the methods and suggestions of controlling final pressure value.

The test method of shallow plate load was used in the bearing capacity of foundation of Yushu City , doing two groups of loading test in different depths and doing survey and comparative test between test point nearby and sites in the same horizon.It gets the law of foundation soil bearing capacity value got by different test methods and provides the basis for Jilin Province to establish the local standards through the comparison of load test and geotechnical test , static cone penetration test and standard penetration test.

The squeezed branch pile is a kind of frictional end bearing pile which is variable cross-section, a new type of pile foundation with characteristics of high bearing capacity and low settlement. In order to explore vertical settlement regularity of the squeezed branch pile, this paper carries out the theoretical analysis and experimental research on the consolidation settlement law of the squeezed branch pile through the numerical method and static load test. The results of numerical analysis and experimental research show that vertical consolidation settlement is reduced along with increase of the squeezed branch pile diameter, and the settlement of the squeezed branch pile is given priority to consolidation.

Because of the excavation of deep foundation pit will have an important impact on the surrounding buildings, causing serious safety risks, In this paper, though the deformation monitoring of deep foundation pit engineering in No.1 Hospital of Jilin University, It has an in-depth analysis and research on the deformation law of foundation pit and surrounding  buildings at the stage of foundation pit construction. The results show that the  deformation monitoring analysis of deep foundation pit engineering can not only realize the construction information of deep foundation pit , correctly guide the engineering construction, prevent engineering accidents, but also help to further improve the theory of foundation pit deformation, provide reliable data for the design.

By finite element method and on the basis of measured data of horizontal static test of pile foundation, the article analyzed horizontal lateral resistance of pile lateral soil under the interaction of piles and soil and horizontal resistance coefficient of foundation soil. The results prove that weighting horizontal resistance coefficient ( m) of foundation soil and the displacement of pile top changed in the reduce of hyperbolic. Meanwhile, it indicates that the constraints of pile top can enhance pile horizontal resistance obviously.

A grid generation method for the three-dimensional arbitrary complex geometry of casting is introduced for the foundry simulation. The approach of a STL (STereo Lithography) model from CAD to a distance field is described in detail. The mesh generated by this approach is based on a fully threaded tree and refined at specific positions according to the distance field. This algorithm may make the mesh become fine at the surface and coarse inside. Several examples are provided to validate this algorithm.

In order to predict the mechanical property during the actual production of gray cast iron, to qualify the casting for the requirement of mechanical property and to control the cost, in this paper a series of anatomy and mechanical property experiments are conducted based on the automobile engine cylinder head processed through the actual production. The actual Brinell Hardness (HB) and the pouring parameters of the cast iron are acquired through the experiment. According to the pouring parameters, the cooling curve is obtained through the Inte CAST software simulation and the cooling rate is also calculated. Based on the existing property prediction model, the Brinell Hardness property prediction model of the engine cylinder head is deduced. The prediction results conform well to the actual data results.

According to the calculation model of the keyhole porfile[1], the 3D point cloud data is calculated. Then, the paper establishes a physical model of the keyhole in the laser welding by using the 3D reverse technology. The adaptive mesh generation of the model is processed by the independent development software. Finally this paper establishes a mathematical model of the temperature field in the laser welding, which considers the factor of the welding velocity. A more accurate temperature field is obtained by using the laser welding solver which is a secondary development of OpenFOAM, adding the Guass surface source and the keyhole volume source, and setting the boundary condition of convection and radiation. The result provides more accurate bases for the welding stress field.

A simplified mathematical model for describing the solidification processing of fluid flow, heat and solute transfer in binary alloys is developed. The conservation equations are numerically solved on a staggered grid by using the control volume-based finite difference method. As the interdendritic flow in the mushy zone is governed by Darcy’s law, the Modified Projection Method is presented for solving the momentum and continuity equations. The solidification processing of Fe-C alloy in rectangular domains is simulated and discussed. The numerical result shows that, by using the Modified Projection Method technique, the presented model is able to predict the macrosegregation formation effectively.

A three-dimensional incompressible two phase flow model of vertical centrifugal casting is proposed to simulate the fluid flow of mould filling process accurately and effectively. The Projection method is adopted to solve the govern equation of the flow field, and the Level Set method is used to capture the free surface. The mold filling of a complex part with thin-wall is simulated. The numerical result shows that the Projection-Level Set method could simulate centrifugal casting effectively. The present study has a guiding significance to the production of vertical centrifugal casting.

Numerical simulation provides a way to improve our understandings of the heat transfer and fluid flow behaviors of the weld pool during laser keyhole welding. However, current numerical studies are only limited to serial simulations which running on a single CPU. In this study, a parallel numerical study of the heat transfer and fluid flow of the weld pool is presented. A mathematical model considering the effect of Marangoni force, buoyancy force, friction force of the mushy zone region and the effect of keyhole is presented. A combined keyhole volume and surface heat source model is also developed. The coupled transient heat transfer and Navier-stokes equations are solved with a high order accuracy parallel projection method. The simulation code is parallelized with the OpenMP language. It is shown that 200% speedup can be achieved on a shared memory quad-core CPU using the presented parallel simulation system. The simulation results agree well with the in-situ high speed CCD video imaging experiments and the literature results.

Using the method of mesomechanics, a represent volume element (RVE) with internal pressure acted on the inner wall of the void is suggested to simulate the hydrogen induced cracking (HIC) in porous ductile materials. Based on this RVE, yield criterion is derived and constitutive model is constructed. Simulations show that the hydrogen pressure intensively reduces the yield stress for porous ductile materials