Advanced Materials Research Vols. 1061-1062

Abstract: Tensile test of low carbon steel was carried out on a universal electronic testing machine. Loading and strain test data of low carbon steel was acquired by means of the tensile test. Based on the measured tensile specimen data, elastic modulus of low carbon steel was calculated. It was found that elastic modulus of low carbon steel varied during tensile process. The damage of low carbon steel under tensile was identified by the calculation of elastic modulus.

Abstract: Copper alloys with high strength and high conductivity are a serial of materials with excellent comprehensive performance. However, the strength and the conductivity are a pair of conflicting factors. To resolve this contradiction, Cu-1.0Cr-0.12Zr alloy was studied in this paper. With optical microscope, scanning electron microscope, Brinell hardness and the arms bridge, effects of heat treatment on microstructure and properties of such alloys was studied,and we strived to find a heat treatment processing to achieve the best match between the conductivity and the strength of the alloy. This paper focused on the study of conductive properties of the alloy. The main factor infuencing the conductivity of the alloy was the content of the soluting elements. The higher the content,the lower the conductivity, and vice versa. The results showed that the best comprehensive properties were obtained after solid solution at 920°C and then aging at 450°C for 180 min.

Abstract: Effect of the solid-solution treatment on the structures and properties of the die-casting AZ91D alloy with mixed rare-earth elements was explored.The results show that the the tensile strength and the elongation ratio δ have been improved by solid-solution treatment.The higher the treatment temperature was,the better the improvement were.With the increase of the temperature,the content of β phase was lower when those of M-RE compound and the refinement α phase were higher.The tensile strength can reach 304.74Mpa and the elongation ratio can reach 11% after the solid-solution treatment of 370°C×16h.

Abstract: The influences of different pulse voltage, pulse frequency, pouring temperature and mold temperature on solidified structure of Mg₉₇Y₂Cu₁ alloy reinforced by long-period ordered structure with compound treatment of pulsed magnetic field and mechanical vibration were studied. The results show that grains of the alloy can be refined greatly with compound treatment. Primary phase degrades from developed dendrites into rosette-shaped crystal. Distribution of second phase is more uniform and continuous, and its volume fraction increases. When the pulse voltage is at 0-280V or the pulse frequency is at 1-10Hz, grain size of the alloy decreases dramatically as pulse voltage or pulse frequency increases. When the pouring temperature is at 660-750°C or the mold temperature is at 20-600 ^oC, grain size of the alloy with compound treatment decreases grossly with the increase of the pouring temperature or the mold temperature.

Abstract: Based on the basic characteristics of Compact Strip Production (CSP), this paper studies the composition design of Nb micro-alloyed pipeline steel, proposed eliminating mixed grains production control technology, also studied the microstructure and properties of steel pipe produced by Electric Resistance Welding ( ERW). Its performance meets API 5L specification and the project technology conditions, used for materiel of steel pipe for oil and gas pipeline project.

Abstract: Studies of the polypropylene grafted with malefic anhydride PP-g-MAH as compatibilizer to toughening polypropylene PP and PMMA blends. When PP/PMMA fixed ratio of 80/20, the effects of PP-g-MAH content on the blend morphology, mechanical properties and thermal properties. With the increase of PP-g-MAH content, strength and impact strength, tensile strength, PMMA/PP/PP-g-MAH blends were first increased and then decreased, and in the PP-g-MAH for 5 copies and reached the maximum value; while the flexural strength increased. The impact strength of the alloy compared with the alloy without the addition of compatibilizer increased about 30%, the tensile strength, bending strength increase obviously. That PP-g-MAH has effects on the morphology and properties of PMMA/PP/ PP-g-MAH blend system.

Abstract: NCu30-4-2-1 alloy was handled by solid solution at 950°Cfor 2h and then taking aging treatment at different temperatures and holding time. The microstructural evolution of NCu30-4-2-1 alloy in the process of aging treatment was investigated by metallographic microscope, X-ray diffractometer and differential scanning calorimetry. The results show that the phases of as-cast NCu30-4-2-1 alloy is composed by dendritic α-Ni-based solid solution and β-Ni₃Si. After solid solution and aging treatment, the block distribution β-Ni₃Si dissolves and many small granular dispersed distribution β'-Ni₃Si precipitate out. With the increase of aging temperature and holding time, metastable β' tends to transform into stable β-Ni₃Si. The precipitation sequence of aged NCu30-4-2-1alloy is supersaturated solid solution of α-Ni, GP zone, β'-Ni₃Si and β-Ni₃Si.

Abstract: In this paper, a gradient-driven non-linear optimization algorithm has been introduced and applied in numerically simulation of a nickel-chromium alloy at elevated temperature. The Chaboche unified constitutive model has been used to describe the cyclic plasticity and viscoplasticity of this alloy. Optimisation algorithm has facilitated a step-by-step method to obtain the initial material parameters, while a non-linear least-square approach were used to obtain the optimised material parameters. Uniaxial experiments were carried to obtain the full cyclic stress-strain and stress relaxation data at 450°C. Satisfactory results have been obtained for the simulation of the transient and steady state cyclic stress-strain and stress relaxation behaviour.

Abstract: NCu30-4-2-1 alloy was treated by the two methods of in situ observation experiment at high temperature and common heat treatment to determine solution temperature. High temperature metallurgical microscope was used to in situ observation of microstructure evolution of NCu30-4-2-1 alloy during heating process. The microstructures of the samples were observed by optical microscope. The results show that the as-cast microstructure of NCu30-4-2-1 alloy is composed by dendritic α-Ni-based solid solution and net-like (α+β) eutectics. The morphology of strengthening phase β-Ni3Si is graininess distributing on the grain boundary. The optimum solution temperature is both determined as 950°C by the two methods. The two methods of in situ observation experiment at high temperature and common heat treatment have comparability.