| Along with the advance of social and economic development, magnesium alloyas a kind of lightweight structure material has many advantages and graduallystepped into our daily life. But we found in the practical application of magnesiumalloy has low strength and toughness problem, insufficient strength seriously inhibitsthe development and application of magnesium alloy. Deformation strengthening andheat treatment is a common way of strengthening alloy, the characteristics of thismethod are easy to operation and low in cost. In this paper, we use metallographicmicrostructure observation, scanning electron microscope (SEM) and energyspectrum analysis, mechanical property testing to study on the microstructure andmechanical properties of heat extrusion state of ZM5alloy and the effect of heattreatment, mainly to the following contents are discussed: the effect of heat extrusionof ZM5alloy; applicable heat treatment process of extruded ZM5alloy; the effect oftwo-step aging of ZM5alloy; to observe the microstructure change after differentprocesses.The experiments proved that after heat extrusion, the strength of ZM5alloyhave highly improvements; for the alloy after extrusion processing, T4T5heattreatment cannot make obvious improvement in performance, among them T4heattreatment will make the recrystallization grain size organization bulky, it`ll havenegative influence on the performance; T6heat treatment can slightly improve theperformance of alloy, use solid solution+two-step aging treatment to the alloy canget a higher alloy organization intensity. During two-step aging, both aging treatmenttemperature and time will affect the performance of alloy, experiments showed thatsolid solution with415℃×10h and two-step aging with100℃×12h+200℃×6h can have higher strength.Then, we have observe the different forms of alloy tissue, through theobservation found that as-cast ZM5alloy in the process of extrusion changed obviously grain crushing and dynamic recrystallization; after solid solution treatmentprocess the recrystallization have grain growth in the alloy, precipitated phase solidsolution into the substrate; after aging treatment, Aluminum and Zinc precipitationagain, it`ll have good strengthening effect on alloy structure. |
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