Mg–0.2 wt%(0.035 at.%)Ce alloy was hot-rolled and its mechanical properties were investigated by conducting tensile and Erichsen tests at room temperature and 433 K. The rolled Mg–Ce alloy exhibited greater elongation to failure and higher stretch formability than the rolled pure Mg. This was attributed to a reduction in basal texture intensity and the splitting of the basal plane by the addition of a small amount of Ce (0.2 wt%). Also, the small amount of Ce strongly affected the recrystallization behavior during hot rolling. Microstructural observation revealed that the prismatic slip was activated in the Mg–Ce alloy. The enhancement of the non-basal slip by the addition of Ce was not attributed to a reduction in the c/a ratio. An increase in stacking fault energy due to the addition of Ce is suggested to play a vital role in the activation of the non-basal slip.

Enhancement of tensile ductility and stretch formability of magnesium by addition of 0.2 wt%(0.035 at%)Ce

The microstructural evolution is examined during the hot compression of magnesium alloy AZ31 for both wrought and as-cast initial microstructures. The influences of strain, temperature, and strain rate on the dynamically recrystallized microstructures are assessed. Both the percentage dynamic recrysallization (DRX) and the dynamically recrystallized grain size were found to be sensitive to the initial microstructure and the applied deformation conditions. Lower Z conditions (lower strain rates and higher temperatures) yield larger dynamically recrystallized grain sizes and increased percentages of DRX, as expected. The rate with which the percentage DRX increases for the as-cast material is considerably lower than for the wrought material. Also, in the as-cast samples, the percentage DRX does not continue to increase toward complete DRX with decreasing Z. These observations may be attributed to the deformation becoming localized in the DRX fraction of the material. Also, the dynamically recrystallized grain size is generally larger in as-cast material than in wrought material, which may be attributed to DRX related to twins and the inhomogeneity of deformation. Orientation maps of the as-cast material (from electron backscattering diffraction (EBSD) data) reveal evidence of discontinuous DRX (DDRX) and DRX related to twins as predominant mechanisms, with some manifestation of continuous DRX (CDRX) and particle-stimulated nucleation (PSN).

Microstructural Development during Hot Working of Mg-3Al-1Zn

Friction stir additive manufacturing for high structural performance through microstructural control in an Mg based WE43 alloy

The effects of cerium (Ce) addition on the microstructure and mechanical properties of ZK60 alloy were investigated using SEM, EBSD, and TEM and by performing tensile tests of indirect-extruded ZK60 alloys with 0.5, 1.0, and 1.5 wt% Ce contents. The variation of hot workability due to Ce addition was also investigated by establishing processing maps of these alloys. The results revealed that Ce addition had an obvious influence, reducing the average grain size and weakening the basal fiber texture of the as-extruded ZK60 alloys; these changes were attributed to the promotion of dynamic recrystallization (DRX) by particle stimulated nucleation (PSN) at Mg–Zn–Ce particles. The yield and tensile strengths were improved by the Ce addition, while the elongation was decreased due to the hard Mg–Zn–Ce particles. It was also found that the hot workability improves up to the addition of 1.0 wt% Ce and then deteriorates.

Effects of cerium addition on the microstructure, mechanical properties and hot workability of ZK60 alloy

The hot working flow stress is examined for wrought and as-cast magnesium alloy AZ31, deformed in both compression and torsion. It is found that the hot deformation behaviour is sensitive to the deformation conditions, initial microstructure and the deformation mode. The peak stresses in compression are higher for as-cast material at low strain rates and high temperatures, whereas they are higher for fine-grained wrought material at high strain rates and low temperatures. Also, the stress–strain curves in torsion exhibit considerably higher strains to the peak flow stress than in compression, particularly at lower temperatures. Most noticeably in the compression of the wrought material, the shape of the stress–strain curves change considerably as the temperature is reduced and the strain rate is increased. These key features of the deformation behaviour are explained in terms of initial grain size, texture, twinning and dynamic recrystallization.

Influence of initial microstructure on the hot working flow stress of Mg-3Al-1Zn

Plastic deformation behaviors of a Mg–Ce–Zn–Zr alloy

The influence of T5 and T6 tempers at 523 K on the mechanical properties and microstructure of hot-rolled WE43 alloy has been studied. The microstructure of the alloy under various conditions was studied using an optical microscope, a transmission electron microscope, and a x-ray diffractometer. The mechanical properties were measured on a tensile testing system. The results show that the hot-rolled WE43 alloy has a substantially higher hardness and strength improvement than the cast WE43 alloy. The hot-rolled WE43 alloy with a T5 temper showed better properties than the alloy with a T6 temper because both strain hardening and age hardening increased the strength of the alloy. In addition, the size of the precipitates after a T5 temper was smaller than that after a T6 temper. The yield strength of the alloy parallel to the rolling direction was higher than that perpendicular to the rolling direction.

/pdf/effect-of-t5-and-t6-tempers-on-a-hot-rolled-we43-magnesium-15icfhpwzj.pdf

Effect of T5 and T6 Tempers on a Hot-Rolled WE43 Magnesium Alloy

The high silicon content Si-Al alloy is a typical heat dissipation material that used in the electrical packaging field. A spray forming process is used to produce a 70%Si-Al alloy specimen as a heat dissipation material with a diameter of 76.2mm (3 inch) and a thickness of 6mm. Then the spray formed Si-Al alloy specimens are hot pressed at 570 C with different pressure ranged from 200MPa to 700MPa to increase their density. The physical properties of the experimental alloy specimen are measured. And the microstructures are observed by using optical microscopy and scanning electronic microscopy. The results show that Spray forming is suitable to produce a 70%Si-Al alloy. The size of primary Si phase in the spray formed 70%Si-Al alloy is refined only 20 30 mm. The relative density of 70%Si-Al alloy after spray forming is about 90%. With a following hot pressure of 700MPa, the relative density value can obtain 98%. The typical physical properties such as the thermal conductivity, coefficient of thermal expansion and electrical conductivity of spray formed 70%Si-Al alloy are acceptable as a heat dissipation material for many electronic packaging applications. [doi:10.2320/matertrans.MRP2007630]

http://www.jstage.jst.go.jp/article/matertrans/49/3/49_MRP2007630/_pdf

Production and Properties of a Spray Formed 70%Si-Al Alloy for Electronic Packaging Applications

The invention discloses a molding method of ultra-thin magnesium alloy plank stuff, which firstly carries out heat preservation of magnesium alloy cast ingots at the temperature of 648 to 688 K for 22 to 25 hours under the protection of inert gases, implements the homogenization treatment of ingot blanks, directly cogs the ingot blanks with heat extrude until the total deformation degree of the heat-extruded and cogged ingot blanks reaches over 40 percent and then implements annealing; the molding method trims the plate blanks after the heat-rolled cogging into required width dimension, implements transverse rolling in a thermal treatment status and controls the heat rolling deformation degree between 20 and 30 percent at the first time, implements longitudinal rolling after the middle annealing, and then implements a plurality of times of transverse rolling, longitudinal rolling, repeated transverse rolling and repeated longitudinal rolling in the thermal treatment status with the assisted middle annealing until the thickness of the plank stuff is 1mm; the molding method implements the cold rolling of the plank stuff with the reduction of 5 percent in each pass, the total deformation degree of the cold rolling between two middle annealing is controlled at 30 percent, and the thickness of the plank stuff after the cold rolling is 0.1mm; the molding method finally implements the flattening and the finishing operation of the plank stuff. The plank stuff produced by the molding method of the invention has tiny crystal grains, even tissue, little defects, lessening cardinal area texture, and improving mechanical, corrosion resistant and electrochemical performance, etc..

Richu Wang

Papers

Plastic deformation behaviors of a Mg–Ce–Zn–Zr alloy

Effect of T5 and T6 Tempers on a Hot-Rolled WE43 Magnesium Alloy

Production and Properties of a Spray Formed 70%Si-Al Alloy for Electronic Packaging Applications

Moulding method of magnesium alloy ultrathin sheet material

Study on the phase equilibria of the Al-Cr-Ti system at 1050 °C