Deformation Micromechanism and Constitutive Analysis Behind the Semisolid Powder Compression of Medical Mg-Zn Alloy

Degradation Adaptability Assessment of Semisolid Powder Molded Mg–Zn–Mn Alloys for Orthopedic Applications

“…This is because the grain refinement is insufficient due to the weakening of pseudo-transgranular liquation cracking (pseudo-TLC) at a low liquid fraction. 17 After 12 days of immersion of Mg−6Zn, the corrosion products are partially clustered on the surface, and an uneven and loose corrosion product film remains, as shown in Figure 3a1. As Mn is added, the corrosion product film becomes denser and even, as shown in Figure 3b1,c1.…”

“…Therefore, many strategies, such as the choice of alloying elements, application of different manufacturing processes, reduction of impurities, and surface modifications, have been applied to regulate the Mg corrosion rate . As for the different manufacturing processes, some new techniques have been developed to prepare medical Mg alloys, such as laser-based powder bed fusion (L-PBF), , wire-arc additive manufacturing (WAAM), , binder jetting, , metal injection molding (MIM), , and semisolid powder molding. − …”

“…Semisolid powder molding proposed by Luo et al combines the advantages of powder forming and thixomolding . In our previous studies, − medical Mg– x Zn ( x = 3, 6, 9 wt %) alloys were prepared by semisolid powder molding at different temperatures, and Mg–6Zn was the best composition based on the microstructures and properties (including mechanical and corrosion resistance properties). However, its degradation rate still does not meet the requirements for bone implants.…”

Deformation behavior and forming process simulation of semi-solid powder rolling based on the combined constitutive model

“…Semi-solid powder forming (SPF) is a novel near-net forming technology that has been widely used in preparing composites, due to its advantages of low forming pressure and temperature, low energy consumption, uniform and fine microstructures, and good capability of proportioning the number and type of enhanced phases at will [1][2][3][4][5][6]. During SPF, powders are deformed and broken into fragments under an external force, and then flow, rearrange and fill pores with liquid and fragments, while liquid solidifies to generate metallurgical bonding between powders and fragments, which consequently forms fine microstructures, makes the material dense, and simultaneously produces new pores [7,8]. Therefore, the process of SPF is very complicated [9,10], and necessary to be further and deeply investigated to improve the product performance.…”

“…The numerical simulation is the best method to study the forming process of SPF but the present simulated constitutive relationships were mostly obtained from dense or porous materials [7,[11][12][13]. However, the material during SPF changes from discontinuous semi-solid particles with an apparent relative-density of 30%-50% into a continuous porous solid body with a relative-density of 90%-100% [14,15].…”