Interfacial Microstructure Analysis of AZ31 Magnesium Alloy during Plastic Deformation Bonding

Abstract

In this study, a plastic deformation process consisting of hot compression at 350 °C and heat treatment at 400 °C was performed to bond AZ31 magnesium alloy. Microstructural evolution around the bonding interface was systematically characterized to investigate the bonding process and clarify the bonding mechanism. When the plastic deformation strain reached 0.6, the bonding zone was full of fine dynamic recrystallized grains and the initial interface was eliminated. The post-heating treatments were conducted to achieve a sound interface bonding. The tensile tests and the corresponding fracture morphologies analysis indicated that the optimum holding time of heat treatment was 8 h. The interfacial bonding strength of the specimens holding for 8 h reached 164.7 MPa, an enhancement of about 9% compared with that of the specimens holding for 1 h. The microstructure analysis indicated that the bonding quality was affected by migration of the interfacial grain boundary (GB), the development of recrystallized grains and the evolution of interfacial oxides around the bonding area.

Influence of Severe Plastic Deformation by Extrusion on Microstructure, Deformation and Thermal Behavior under Tension of Magnesium Alloy Mg-2.9Y-1.3Nd

“…The structure for the extruded state is dominated by a weak crystallographic texture of the <001> type. The inverse pole figures are presented for different external sections in the crystal: longitudinal X0, transverse Y0, and normal (axial) Z0 in three main planes (0001), (01-10), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). As one can see, in the recrystallized state, the inverse pole figures have clear maxima (Figure 4a), and the maximum reflection density is not concentrated near a particular crystallographic direction.…”

“…Finally, magnesium alloys have an optimal modulus of elasticity (40)(41)(42)(43)(44)(45), similar to that of the native bone [13,14]. Alloying of magnesium with rare earth metals (RE), such as Y, Nd, Gd, Ce, Dy, etc., leads to the enhancement of strength characteristics, and to increases in plasticity and corrosion resistance [15][16][17][18]. However, in some cases, the achieved level of strength properties does not meet the necessary requirements.…”

“…In view of the above, various deformation methods were proved to be very promising, including severe plastic deformation (SPD), for example, equal-channel angular pressing (ECAP), abc-forging, rotational forging, extrusion, etc. These methods allow one to obtain a high level of mechanical properties in metals by grinding grain to an ultrafine-grained (UFG) state [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. In this case, it becomes possible to significantly improve the mechanical properties of alloys.…”