摘要：Solution and quenching heat treatments are generally carried out in a roller hearth furnace for large-scale thick aluminum alloy ***,the asymmetric or uneven spray water flow rate is inevitable under industrial production conditions,which leads to an asymmetric residual stress *** spray quenching treatment was conducted on self-designed spray equipment,and the residual stress along the thickness direction was measured by a layer removal method based on *** the asymmetric spray quenching condition,the subsurface stress of the high-flow rate surface was lower than that of the low-flow rate surface,and the difference between the two subsurface stresses increased with the increase in the difference in water flow *** subsurface stress underneath the surface with a water flow rate of 0.60 m^(3)/h was 15.38 MPa less than that of 0.15 m^(3)/*** simulated residual stress by finite element(FE)method of the high heat transfer coefficient(HTC)surface was less than that of the low HTC surface,which is consistent with the experimental *** FE model can be used to analyze the strain and stress evolution and predict the quenched stress magnitude and distribution.

摘要：Combining the design of experiments(DOE)and three-dimensional finite element(3D-FE)method,a sequential multiobjectiveoptimization of larger diameter thin-walled(LDTW)Al-alloy tube bending under uncertainties was proposed andimplemented based on the deterministic design *** the fractional factorial design,the significant noise factors are obtained,viz,variations of tube properties,fluctuations of tube geometries and *** the virtual Taguchi’s DOE of inner and outerarrays,considering three major defects,the robust optimization of LDTW Al-alloy tube bending is achieved and *** thebending tools,the robust design of mandrel diameter was conducted under the fluctuations of tube properties,friction and *** the processing parameters,considering the variations of friction,material properties and manufacture deviation ofmandrel,the robust design of mandrel extension length and boosting ratio is realized.

摘要：Hot plane strain compression tests of 6013 aluminum alloy were conducted within the temperature range of 613?773 K and the strain rate range of 0.001?10 s?1. Based on the corrected experimental data with temperature compensation, Kriging method is selected to model the constitutive relationship among flow stress, temperature, strain rate and strain. The predictability and reliability of the constructed Kriging model are evaluated by statistical measures, comparative analysis and leave-one-out cross-validation (LOO-CV). The accuracy of Kriging model is validated by the R-value of 0.999 and the AARE of 0.478%. Meanwhile, its superiority has been demonstrated while comparing with the improved Arrhenius-type model. Furthermore, the generalization capability of Kriging model is identified by LOO-CV with 25 times of testing. It is indicated that Kriging method is competent to develop accurate model for describing the hot deformation behavior and predicting the flow stress even beyond the experimental conditions in hot compression tests.

摘要：In this study, a novel punch toolset was developed to investigate the hot stamping of AA6082-T4 sheet. The effect of the process parameters, including forming temperature, punching velocity, friction coefficient, and blank holder force(BHF) on formability was quantified using Taguchi design, analysis of variance(ANOVA) and mathematical statistics. The finite element(FE) model has been established in software Pamstamp for simulation and analysis of their effects on the minimum thickness and thickness variation of the hot-stamped component. The major factors influencing the minimum thickness of the hot-stamped part has been found to be BHF and friction coefficient with influence significance of 35.3% and 34.88%, respectively. Additionally, punch velocity and BHF affect the thickness deviation significantly with influence significance of 40.43% and 35.42%, respectively. Furthermore, a serious thinning occurs on the punch corner region of the hot-stamped cup when the BHF is larger than 2.4 kN. The thickness deviation of the hotformed cup has been found to be firstly decreased and then increased with the increase of punch velocity. Low friction coefficient between punch and blank led to crack at bottom centre of the cup. Moreover, different type, phenomenon and mechanism of defects occurring during hot stamping process, such as crack and wrinkling, were discussed. The crack mode was dimple-dominated ductile fracture, which was induced by micro-void nucleation, growth and coalescence.

摘要：The automobile suspension parts of a high strength 6xxx aluminum alloy were produced using a novel technique known as near net shape casting for forging stock preparation. Based on the outline dimension of the forging stock, the shape of the ingot was designed as the near net shape and its casting process was studied by the numerical simulation and experimental investigation. The results show that the shrinkage of the ingot was highly correlated to its shape parameters and could be successfully forecast by the stimulation model. The casting parameters of the near net shape ingot were optimized and the near net shape 6xxx aluminum alloy ingots free of defects were cast in the laboratory. In order to obtain high performance forged suspension parts, the hot compression tests of the ingot were carried out. The results show that the subgrain fraction of the forged ingot was strongly affected by Zener-Hollomon parameters （Z parameters）. The intermediate Z parameters, 1.09×10^16 s^-1, will contribute to the larger number fraction of subgrains inside the forged ingot, which contributes to the high performance of the forged products.

摘要：Stepped heating treatment has been applied to aluminum alloy thick plate to improve the mechanical performance and corrosion *** temperature control of the plate is the difficulty in engineering *** heating process,the calculation of surface heat transfer coefficient and the accurate temperature control method were studied based on measured heating temperature for the large-size thick *** results show that,the temperature difference between the surface and center of the thick plate is *** on the temperature uniformity,the surface heat transfer coefficient was calculated,and it is constant below300°C,but grows greatly over300°***,a lumped parameter method(LPM)was developed to predict the plate temperature.A stepped solution treatment was designed by using LPM,and verified by finite element method(FEM)and *** curves calculated by LPM and FEM agree well with the experimental data,and the LPM is more convenient in engineering application.

摘要：As a brazing foil, 4004 A1 alloy has good welding performance. However, the high Si content decreases the plasticity of the alloy. In order to improve the plasticity of 4004 A1 alloy and subsequently improve the productivity of 4004 AI foil, 4004 A1 alloy was modified by RE-Ba-Sb. As a comparison, the 4004 A1 alloy was also modified by RE with different addition. The tensile properties of the alloy reach the best when the addition of RE was 0.2%, in which the tensile strength and elongation were 194 MPa and 5%, respectively. For RE-Ba-Sb modification, the addition of three elements was optimized by orthogonal analysis. The results showed that the greatest impact parameter of RE-Ba-Sb modification was RE addition, followed by addition of Ba and Sb. The optimum addition amounts of RE, Ba and Sb obtained by orthogonal analyses were 0.01%, 0.3%, and 0.05%, respectively. The tensile strength and the elongation of 4004 A1 alloy modified by the optimal modification process were 224 MPa and 6%, respectively. The amount of RE addition in RE-Ba-Sb modification is lower than that in RE modification.

摘要：The deformation zone of CONFORM extrusion was divided into primary gripping zone,gripping zone,conical expansion chamber zone,cylindrical zone and sizing zone of die,and corresponding force equilibrium equations were established using the Slab *** deformation force formulae of CONFORM machine at any wrapping angle with an expansion chamber were *** on pure aluminum and Al-5%Ti-1%B alloy was conducted on the CONFORM machine *** resistance to deformation of Al-5%Ti-1%B alloy at the deformation temperature of 400℃ and the strain rate of 3.07 s-1 was measured to be 50 MPa using Gleeble-1500 thermal simulation *** calculation results of deformation forces for CONFORM process with an expansion chamber for pure aluminum and Al-5%Ti-1%B alloy were *** experimental CONFORM radial force is in agreement with the radial force obtained by theoretical formula.

摘要：This paper presents an experimental investigation of longitudinally welded aluminum alloy I-section columns subjected to pure axial *** specimens were fabricated using 6061-T6 heat-treated aluminum *** test program included 20 column tests which were separated into 2 test series of different types of welding *** test series contained 10 *** the specimens were welded using the Tungsten Inert Gas welding *** length of the specimens ranged from 442 to 2433 mm in order to obtain a column curve for each test *** observed failure mode for the column tests includes mainly flexural buckling around the minor axis and the major axis by applying support except for one column(ZP 1217-1)which buckled in the local zone and some columns which failed in the *** test strengths were compared with the design strengths predicted by the European Code and China Code for aluminum *** purpose of this paper is to present the tests results of two typically longitudinally welded I-section columns,and to check the accuracy of the design rules in the current specifications.