Enhancement of Strength and Hot Workability of AZX312 Magnesium Alloy by Disintegrated Melt Deposition (DMD) Processing in Contrast to Permanent Mold Casting

Abstract

AZX312 (AZ31-2Ca) magnesium alloy, with starting conditions of as-cast (AC), casthomogenized (CH), and disintegrated melt deposition (DMD), is examined in terms of its compressive strength and hot working behavior to establish the relative merits and limitations of these processing routes. Processing maps are developed in the temperature range of 300-500 • C and strain rate range of 0.0003-10 s −1 , and mechanisms of hot deformation are established based on microstructures, tensile ductility, and activation parameters. The alloy in AC and CH conditions has a large grain size with intermetallic phases at the grain boundaries and in the matrix. In DMD processed alloy, the grain size is very small and the phases are refined and distributed uniformly. The compressive strength is significantly improved by DMD processing, which is attributed to the grain refinement. The processing maps for AC and CH conditions are similar, exhibiting only a single workability domain, while the DMD processed alloy exhibited three domains that enhanced workability. The additional workability domain at higher strain rates is an advantage in designing forming processes that facilitates faster production, while the fine grain size produced by a finishing operation in the lower temperature domain will improve the mechanical properties of the product.

The Promise of Turning Induced Deformation Process for Synthesizing Magnesium Based Materials with Superior Mechanical Response

“…Mg materials in their bulk form are first cast into ingots using the disintegrated melt deposition method [23] to form the basis for this processing method. The resulting cast ingot then has its surfaces machined off to eliminate surficial contaminants.…”

An Investigation into the Potential of Turning Induced Deformation Technique for Developing Porous Magnesium and Mg-SiO2 Nanocomposite

“…The raw materials were processed into ingots using the disintegrated melt deposition (DMD) method with a target superheat temperature of 750 °C, followed by stirring of the melt at 450 rpm for 5 min [ 35 ], after which turnings were generated from ingots using the TID secondary processing method [ 28 ] at 1.5 mm depth of cut and 55 mm/min average cutting speed. The resulting turnings were then compacted using a hydraulic press at a pressure of 1.03 MPa with a holding time of 60 s in cylindrical dies of 10 and 15 mm diameter to generate porous cylindrical compacts for further characterisation.…”

Deformation Behavior of the Alloys under Simple and Combined Loading Conditions at Various Deformation Rate

“…In total, eight articles [1][2][3][4][5][6][7][8] have been presented in the present Special Issue. Their target metals are broad, ranging from an advanced steel [1] to alloys composed of light metals such as magnesium [2], titanium [3], and aluminum [3][4][5][6], as well as alloys of a smart Ni-Ti system with a shape memory effect [7] and depleted uranium [8]. Almost all target metals are commonly used in industry.…”

“…The following four experimental works [1,2,4,8] discuss from metallurgical points of view. The microstructural studies are done as well by using TEM, Electron Back Scatter Diffraction (EBSD), or Energy Dispersive Spectroscopy (EDS).…”

“…They found that hardening by means of back stress plays an important role for this HSSS due to load transfer and strain partitioning between harder and softer phases. Rao et al [2] examined AZX312 magnesium alloys with different initial processing in terms of its compressive strength and hot working behavior. They developed maps for the processing at the various temperatures and at strain rates ranging from 10 −4 to 10 s −1 .…”