Effect of Grain Particle Size on Quality of Multi-grain Chips Under Screw Extrusion Processing

Multi-grain chips processed by screw extrusion processing have high nutrition and production value with a low glycemic index.To analyze the effects of particle sizes on the qualities of multi-grain chips extrusion processing by using a single screw extruder,mesh numbers were selected as 80,100 and 120 to describe different grain particle sizes.It was found that the particle sizes of the raw materials had effects on the basic components,sensory properties,texture properties,antioxidant activities and in vitro digestibilities of extruded chips.The results showed that with the decrease of particle sizes,the moisture contents,starch contents of the chips decreased,and fat contents,dietary fiber contents increased.The edible qualities of the chips increased with the decrease of the grain sizes of raw materials.The antioxidant capacities and estimated glycemic indexes of the three kinds of chips showed a trend of decreasing first,and then increasing with the decrease of particle sizes.Correlation analysis showed that the total antioxidant capacities of chips were negatively correlated with the estimated glycemic indexes.The research results provided valuable guidance for the quality processing of multi-grain chips under extrusion processing.

Hot Extrusion Processing of Al–Li Alloy Profiles and Related Issues:A Review

Al-Li alloy is a new structural material with the advantages of lightweight and high strength.The extrusion profiles of Al-Li alloy are widely used in aerospace and other fields,which can significantly reduce the weight of the aerospace equipment and improve their carrying capacity and service performance.Particular service conditions of structural components in aeronautical and space areas put forward strict requirements on microstructure,mechanical properties,and dimensional precision of Al-Li alloy profiles.Therefore,it places higher requirements on the shape forming and microstructure controlling of the Al-Li alloy profiles.The manufacturing process of the profiles involves billet homogenization,hot extrusion,solution and quenching treatments,artificial aging,and others.The parameters of each process as well as the die structure have important effects on the final performance of the profiles.This article summarizes the main applications and key mechanical properties of Al-Li alloy extrusion profiles.The technologies related to the manufacturing process of the extrusion profiles are summarized and analyzed.The related studies about the evolutions of the microstructure and mechanical properties during homogenization and extrusion processes are reviewed.The developments of the solid solution and quenching treatments as well as the aging strengthening technology for extruded Al-Li alloy profiles are also introduced.The scientific problems and key technologies that need to be solved in the manufacturing of Al-Li alloy extrusion profiles are presented,and the prospect for future development trends in these fields is given.

Effects of Extrusion Processing on Microstructure of 7075Al Alloy in the Semi-solid State

A recrystallization and partial melting(RAP) process was introduced to prepare the semi-solid 7075 aluminum alloy used for thixoforming. In order to obtain an ideal semi-solid microstructure, a series of extrusion experiments were conducted to comparatively investigate the optimum extrusion process parameters. Commercial 7075 Al alloy samples were firstly extruded with varying extrusion ratios below the recrystallization temperature followed by homogenization, then these samples were reheated to the semi-solid state and held in the range of 5 to 50 minutes. The experimental results show that varying process cause the difference in the deformation degree and microstructure for as-extruded samples, resulting in various semi-solid microstructure. It is verified that the formation of equiaxed grains in semi-solid microstructure depends on recrystallization behavior of extruded samples during partial melting. Both relative high extrusion temperature and low extrusion ratio lead to high volume fraction of recrystallized area, thus entirely equiaxed solid grains in semi-solid 7075 Al alloy samples can be obtained finally. In addition, Ostwald ripening was determined as the dominate coarsening mechanism of solid grains in semi-solid state for this 7075 Al alloy during the RAP route. The influence of predeformation on recrystallization behavior of this 7075 Al alloy was discussed in detail.

Simulation Analysis of Extrusion Process of Equilateral L-shaped Aluminum Profiles Based on Deform-3D

The extrusion deformation process of L-shaped aluminum profiles was numerically simulated using the finite element program Deform-3D.The simulation findings revealed that the deformation of the profiles was mostly caused by unequal material flow velocity,which resulted in the profiles bending.Determine the impact of extrusion parameters on the bending deformation of the profile after studying various parameters that may affect the material flow mode(hole position,extrusion speed).

Unique microstructure and property of a 2024 aluminum alloy subjected to upsetting extrusion multiple processing

The microstructure and hardness of a 2024 aluminum alloy subjected tomulti-pass upsetting extrusion at ambient temperature were studied. Experimental results indicatedthat with the number of upsetting extrusion passes increasing, the grains of the alloy are graduallyrefined and the hardness increases correspondingly. After ten passes of upsetting extrusionprocessing, the grain size decreases to less than 200 nm in diameter and the sample maintains itsoriginal shape, while the hardness is double owing to equal-axial ultrafine grains and workhardening effect caused by large plastic deformation.

Dynamical Solidification Behaviors and Metal Flow during Continuous Semisolid Extrusion Process of AZ31 Alloy

In this paper, a novel near-net-shape forming process, continuous semisolid extrusion process （CSEP） of AZ31 alloy was proposed, and the dynamical solidification behaviors and metal flow during the process were firstly investigated. During casting AZ31 alloy by this process, non-uniform microstructure distributions and non- equilibrium solidification region near the roll surface were found in the roll-shoe gap. Microstructural evolution from dendrite to rosette and spherical grains was observed during the casting by CSEP. Casting temperature, roll-shoe gap width and cooling ability have great effect on casting process and metal flow, so these factors should be carefully controlled, a proper casting temperature of 710-750℃ is suggested. The white α phases were strongly stretched during the processing, and the remnant liquids are correspondingly distributes along the solid phase boundaries and also show stripped lines.

Fabrication of fine-grained,high strength and toughness Mg alloy by extrusion−shearing process

A novel extrusion-shearing(ES) composite process was designed to fabricate fine-grained, high strength and tough magnesium alloy. The structural parameters of an ES die were optimized by conducting an orthogonal simulation experiment using finite element software Deform-3D, and Mg-3 Zn-0.6 Ca-0.6 Zr(ZXK310) alloy was processed using the ES die. The results show that the optimized structural parameters of ES die are extrusion angle(α) of 90°, extrusion section height(h) of 15 mm and inner fillet radius(r) of 10 mm. After ES at an extrusion temperature and a die temperature of 350 °C, ZXK310 alloy exhibited good ES forming ability, and obvious dynamic recrystallization occurred in the forming area. The grain size decreased from 1.42 μm of extrusion area to 0.85 μm of the forming area. Owing to the pinning of second phase and formation of ultrafine grains, the tensile strength, yield strength and elongation of alloy reached 362 MPa, 289 MPa and 21.7%, respectively.

Effect of hot extrusion process on microstructure and mechanical properties of hypereutectic Al-Si alloys

The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring,and the microstructure and mechanical properties of the alloy were studied.The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%,respectively with the extrusion ratio of 10,and 263.2 MPa and 5.4%,respectively with extrusion ratio of 20.This indicates that the mechanical properties of the alloy are obviously improved with the increase of extrusion ratio.After hot extruded,the primary Si,eutectic Si,Mg2Si,AlNi,Al7Cu4Ni and Al-Si-Mn-Fe-Cr-Mo phases are refined to different extent,and the efficiency of refinement is obvious more and more with the increase of extrusion ratio.After T6 heat treatment,the sharp corners of these phases become passivated and roundish,and the mechanical properties are improved.The ultimate tensile strength of the extruded alloy after T6 heat treatment reaches 335.3 MPa with extrusion ratio of 10 and 353.6 MPa with extrusion ratio of 20.

Effects of process parameters and die geometry on longitudinal welds quality in aluminum porthole die extrusion process

By using the rigid-visco-plasticity finite element method, the welding process of aluminum porthole die extrusion to form a tube was simulated based on Deform-3D software. The welding chamber height （H）, back dimension of die leg （D）, process velocity and initial billet temperature were used in FE simulations so as to determine the conditions in which better longitudinal welding quality can be obtained. According to K criterion, the local welding parameters such as welding pressure, effective stress and welding path length on the welding plane are linked to longitudinal welds quality. Simulation turns out that pressure-to-effective stress ratio （ρ/σ） and welding path length （L） are the key factors affecting the welding quality, Higher welding chamber best and sharper die leg give better welding quality. When H=10 mm and D=0.4 mm, the longitudinal welds have the best quality. Higher process velocity decreases welds quality. The proper velocity is 10 mm/s for this simulation. In a certain range, higher temperature is beneficial to the longitudinal welds. It is found that both 450 and 465℃ can satisfy the requirements of the longitudinal welds.

Plant-based meat substitutes by high-moisture extrusion:Visualizing the whole process in data systematically from raw material to the products

High-moisture extrusion technology should be considered one of the best choices for producing plant-based meat substitutes with the rich fibrous structure offered by real animal meat products.Unfortunately,the extrusion process has been seen as a“black box”with limited information about what occurs inside,causing serious obstacles in developing meat substitutes.This study designed a high-moisture extrusion process and developed 10 new plant-based meat substitutes comparable to the fibrous structure of real animal meat.The study used the Feature-Augmented Principal Component Analysis(FA-PCA)method to visualize and understand the whole extrusion process in three ways systematically and accurately.It established six sets of mathematical models of the high-moisture extrusion process based on 8000 pieces of data,including five types of parameters.The FA-PCA method improved the R^(2) values significantly compared with the PCA method.The Way 3 was the best to predict product quality(Z),demonstrating that the gradually molecular conformational changes(Y^(n'))were critical in controlling the final quality of the plant-based meat substitutes.Moreover,the first visualization platform software for the high-moisture extrusion process has been established to clearly show the“black box”by combining the virtual simulation technology.Through the software,some practice work such as equipment installation,parameter adjustment,equipment disassembly,and data prediction can be easily achieved.

Deformation division of metal flow behavior during extrusion process of 7075 aluminum alloy

To reduce defects caused by non-homogeneous metal flow in conventional extrusion,a die with guiding angle was designed to improve the metal flow behavior. The characteristic quantities such as the second invariant of the deviator stress J2 and Lode's coefficient μ were employed for the division of deformation area. The results show that when the metal is extruded with the guiding angle,no metal flow interface forms at the container's bottom,the dead zone completely disappears,the deformation types of the metal in the plastic deformation area change from three types to one type of tension,and the homogeneity of the deformation as well as metal flow are greatly improved. The non-homogeneous metal flow at the final stage of extrusion is improved,reducing the shrinkage hole at the axis end. The radial stress of the furthest point from the axis is transformed from tensile stress to compressive stress and the axial stress,and decreased from 70.8 to 34.8 MPa. Therefore,the surface cracks caused by additional stress are greatly reduced.

Prediction of central bursting defects in rod extrusion process with upper bound analysis method

The prediction of central bursting defects in the rod extrusion process through conical dies using the upper bound analysisis investigated. A kinematically admissible velocity field, including the radial and angular velocity components, is proposed. A newcriterion is presented to predict the occurrence of the central bursting defects. Parameter bobt, which represents the risk probability ofcracking, is proposed. It is calculated using the shape of the boundary at the entrance by minimizing the total power dissipationduring the extrusion process. When bobt is equal to or greater than bcr, central bursting occurs. Furthermore, the quantitativerelationships between central bursting defects and process parameters （semi die angle, reduction in area and frictional factor） arestudied. The results show that the central bursting defects are affected primarily by the reduction in area and the friction factor. Thepresented criterion is verified by comparing with the FEM simulation data and the results of the published paper.

AN ADAPTIVE EFG-FE COUPLING METHOD FOR THE NUMERICAL SIMULATION OF EXTRUSION PROCESSES

An adaptive EFG-FE coupling method is proposed and developed for the numerical simulation of lateral extrusion and forward-backward extrusion. Initially, the simulation has been implemented by using a conventional FE model. During the deforming process, mesh quality is checked at every incremental step. Distorted elements are automatically converted to EFG nodes, whereas, the less distorted elements are reserved. A new algorithm to generate EFG nodes and interface elements is presented. This method is capable of dealing with large deformation and has higher computational efficiency than using an EFG method wholly. Numerical results demonstrate that the adaptive EFG-FE coupling method has reasonable accuracy and is effective for local bulk metal forming such as extrusion processes.

ANALYSIS OF SURFACE CRACK ON FORWARD EXTRUDING BAR DURING AXISYMMETRIC CUP-BAR COMBINED EXTRUSION PROCESS

In this paper, the kinematically admissible velocity field with surface crack on forward extruding bar is put forward during the axisymmetric cup-bar combined extrusion process, in accordance with the results of model experiments.On the basis of velocity field, the necessary condition for surface crack formation on the forward extruding bar is derived, with the help of upper bound theorem and the minimum energy principle. Meanwhile, the relationships between surface crack formation and combination of reduction in area for the part of forward and backward extursions relative residual thickness of billet (T/R0),frictional factor (m) or relative land length of ram and chamber are calculated during the extrusion process. Therefore, whether the surface crack on forward exturding bar occurs can be predicted before extruding the lower-plasticity metals for axisymmetric cup-bar combined extrusion process.The analytical results agree very well with experimental results of aluminium alloy LY12 (ASTM 2024) and LC4 (ASTM 7075).

Microstructure and mechanical properties of Mg–Zn–(Nd)–Zr alloys with different extrusion processes

The effect of Nd addition and the influence of extrusion processes on the microstructure and mechanical properties of Mg-6Zn-0.5Zr（ZK60） and Mg-6Zn-1.5Nd-0.5Zr（ZKNd602） alloys were investigated. Nd element can obviously refine the microstructure of both as-cast and asextruded Mg-Zn-Nd-Zr alloy. All of the extruded alloys exhibit a bimodal grain structure composed of equiaxedfine recrystallized（DRXed） grains and elongated coarse un DRXed grains. It is necessary to achieve high strength,particularly the yield strength, for ZKNd602 alloy, when it is extruded with a lower extrusion temperature, a suitable extrusion ratio and a relatively lower extrusion ram speed. In this study, the ultimate tensile strength（UTS）,yield strength（YS） and elongation（El） of the extruded ZKNd602 alloy were 421 MPa, 402 MPa and 6.7 %,respectively, with extrusion temperature of 290 °C, extrusion ratio of 18：1 and a ram speed of approximate0.4 mm·s^（-1）. Meanwhile, the extrusion process has obvious effects on the room-temperature properties but weak effects on the high-temperature properties.

Development and sensing performance study of a smart CFRP cable assembled by multi-group anchorage units

Carbon fiber reinforced polymer(CFRP)can be applied for bridge cables due to its excellent properties.As the important load-bearing structural component,real-time force monitoring of the CFRP cable is required.This paper presents a new smart CFRP cable that combines the self-sensing rods with embedded sensors and the anchorage system using extrusion technology.By embedding optical fiber(OF)and coaxial cable Fabry-Perot interferometer(CCFPI)into CFRP rods respectively,two types of self-sensing rods(CFRP-OF rod and CFRP-CCFPI rod)were fabricated.A new anchorage unit using an extrusion process was proposed as a basic component of smart CFRP cables.Anchorage units holding a CFRP-OF rod and a CFRP-CCFPI rod were tested to obtain their sensing and mechanical properties.Three ancho-rage units were assembled to form a smart CFRP cable with self-sensing functionality.A verification test was carried out to confirm the capabil-ity of monitoring the cable force.The test results demonstrate that the smart CFRP cable composed of multiple anchorage units has good potential in bridge engineering.