Papers by Keyword: WE43 Magnesium Alloy

Abstract: Biodegradable magnesium alloy WE43 (Mg-4Y-3RE) has received great attention in orthopaedic applications as it can dissolve completely after bone tissue repair, eliminating the need for a second surgery to remove the WE43 implant. However, the rapid degradation of WE43 implants during bone healing remains a concern. Rapid degradation can deteriorate the mechanical strength and generate a significant amount of hydrogen gas via corrosion in physiological environments, negatively affecting bone healing and the surrounding tissues. To overcome the rapid degradation of medical implants, one commonly used method is surface modification via laser surface melting (LSM) to alter the surface microstructures and improve the corrosion resistance. This paper investigates the possibility of applying LSM technique to refine the surface microstructures of WE43 alloy and compares the microstructures induced by LSM with the extruded alloy without laser treatment. Results show significant grain refinement after LSM with average grain size decreased to 3μm as compared to 5μm before LSM, approximately 40% reduction in grain size. Different types of grain morphology are also identified at different locations in the melt pool due to different temperature gradients and cooling rates. It is observed that the depth of the melt pool increases with increasing laser power and decreasing laser scanning speed due to the higher heat input. It is also observed that grain size decreases with decreasing laser power and increasing laser scanning speed due to increased cooling rate. Results from this study show that LSM, a form of rapid solidification processing, can form a predominantly basal crystallographic texture, homogenise and refine the surface microstructures of WE43, which are beneficial for corrosion resistance.

Abstract: The effects of quenching rate on the microstructures and mechanical properties of the heat treatable Mg-4.2Y-2.3Nd-1.0Gd-0.6Zr (wt.%) (WE43) sand-cast alloy have been studied using a combination of mechanical testing, Vickers hardness testing, optical microscopy (OM) and scanning electron microscope (SEM). Two quenching conditions, either air quenching or 60°C water quenching, were employed. The results indicate that some precipitates have formed in the matrix and grain boundaries in the air-quenched solutionized alloy. And the Vickers hardness and yield strength (YS) is HV77 and 155 MPa, respectively, which is slightly more than the 60°C water-quenched solutionized alloy. However, the ultimate tensile strength (UTS) and yield strength (YS) of the peak-aged at 250°C (T6) of the two quenching conditions are both 273 MPa and 212 MPa, respectively. And they have similar age hardening curves at 250°C and the T6 microstructure. So the results indicate that in this work of quenching rate range WE43 alloy has few quench sensitivity effect.

Abstract: Magnesium alloys of Mg-Y-RE-Zr series are characterized by creep resistance up to a temperature of 250 ° C, and can work up to a temperature of 300oC. These properties allow for the application of alloys of Mg-Y-RE-Zr series for the elements of racing car engines operating in the conditions of high loads and temperatures. The requirement of high reliability components of aircraft propulsion system, with high strength and corrosion resistance, also led to the use of these alloys in the aerospace industry. Welding technologies in cast magnesium alloys are applied in order to repair defects in castings, occurring in the casting process, as well as to regenerate worn out castings. Joints made of magnesium alloys should have at least the same properties as a finished casting. The literature lacks information on the properties of joints welded of cast magnesium alloys.This work includes examination of influence of heat treatment on creep resistance of alloy WE43. Material for the study comprised joints made by the TIG method, welded in the cast state. Creep tests were carried out on joints without heat treatment and joints after heat treatment. The tests were performed at the temperatures of 200 ° C and 250 ° C during 100h. It was found that there is an increase in creep resistance of the joints after heat treatment.

Abstract: Compared with the actual operation, computational simulation will save the cost and provide more valuable references or guiding significance for the real production. Using professional forming software DEFORM-3D, the upsetting process of WE43 magnesium alloy was simulated. Based on the actual flow stress data, the simulation model of WE43 magnesium alloy was created in DEFORM-3D. Results show that the uniform distribution of the temperature of WE43 magnesium alloy during the forming process is beneficial to the structural homogeneity and contributes to excellent flowing property. There is the stress concentration in the edge and slide face of the billet. So during the process of compression, the fracture will appear earlier in the edge and slide face of the sample.