Nd and T4 heat treatment on AM60 magnesium alloy microstructure and mechanical properties

Title: Nd and T4 heat treatment on AM60 magnesium alloy microstructure and mechanical properties
　　Author: Guojun
　　Degree-granting unit: Taiyuan University of Technology
　　Keywords: AM60 magnesium alloy;; Nd elements;; heat treatment;; microstructure;; mechanical properties
　　Summary:
　　Magnesium alloys have low density, high strength, high stiffness, damping, dimensional stability, machinability and good electromagnetic shielding, etc., are widely used in automotive, electronics, aerospace and other industries. AM series Magnetic lifter magnesium alloy which is used for auto parts on the first magnesium alloy, want to meet the performance requirements of automotive wheels, must increase its robust performance and robust performance matching to solve the problem.
　　In this study, the vacuum resistance furnace melting alloy AM60-xNd prepared sample, the temperature at 683K and different samples within the time frame for the solution treatment, and after solution heat treatment of alloys AM60-0.3Nd the artificial aging treatment. With spark atomic emission spectrometer, plasma spectrometer, X-Ray diffraction, optical microscope, field emission scanning electron microscopy and other means to determine the sample composition, microstructure and structure of the machine with a tensile specimen, measured Vickers hardness tester The mechanical properties of the sample. With the experimental determination of the data, analysis, research the solution time, Nd content on the AM60-xNd alloy mechanical properties, microstructure and the changes of structure and explore its mechanism. For the development of a new type of high strength and high toughness magnesium alloy material provides the basis of experimental data.
　　Through research and analysis, the following conclusions:
　　1) In the AM60 alloy after adding rare earth elements Nd, caused significant changes in alloy, with the Nd content increases, α-Mg matrix phase refinement, mesh size larger continuous phase β-Mg17Al12 gradual separation, change is intermittent, dispersed bone-shaped, and tend to granular; and point-like, there is a growing block of Al11Nd3 phase, and aggregation tendency increases, needle-like, short rod-like Al11Nd3 phase has thicker, longer, bifurcation the trend.
　　2) AM60-xNd alloy after T4 treatment, alloy finer grain size, β-Mg17Al12 phase decomposition, dissolved into the matrix alloy, Al11Nd3 morphology changes slightly. σb, σ0.2 and δ of the peak from the cast to 0.9% Nd 0.3% Nd, the peak reached 239Mpa, 138Mpa, 8%. ; Σb, σ0.2, δ and Nd elements in solid solution strengthening by the HV and Al11Nd3 dispersed phase morphology, the number of effects.
　　3) AM60-0.3Nd alloy processed by T61, β-Mg17Al12 phase and in grain boundaries, grain refinement 3.0 times the average grain size of 30μm, morphology and size changed significantly over-cast, spherical earth with and becomes http://www.999magnet.com/products/131-magnetic-lifter massive. The hardness, yield strength increased by an average of 8.7%, 9.2%, the alloy tensile strength, elongation increased by an average of 23.9%, 33.3%, the maximum tensile strength reached 262MPa.
　　4) rare earth alloy Nd was added to make these micro-plasticity fracture occurs, the system activates a non-slip base results, thus increasing the alloy plasticity.
　　The innovation of this study is that by studying the rare earth element and heat treatment process of coagulation AM60-xNd alloy composition, and mechanical properties of the impact of changes in the mechanism, the development of AM60 alloy with Nd system, its strength, toughness than the AM60- 0.3% Nd magnesium good gold numbers.
　　Degree Year: 2010