| Mn-Cu alloys is a kind of highly damping alloy,in which M2052 is widely used as a high damping alloy with excellent damping performance,comprehensive mechanical properties and mechanical processing performance.At present,M2052alloy is usually fabricated by conventional casting and forging.As a new method,Selective laser melting technology?SLM?enables direct manufacturing of products with the technical features of rapid and efficient formation of complex structural parts.The study has explored optimizing the process parameters of M2052 alloy in SLM.In addition,the heat treatment process of M2052 alloy fabricated by SLM has been explored to the effects of heat treatment on the microstructure,mechanical properties and on the correlation of strain amplitude,strain frequency temperature characteristics and damping capabilities.The study investigates the effects of parameters such as laser power,scanning speed and spot spacing on forming quality of M2052 alloy fabricated by SLM through comprehensive experiment.Explored the influence of process parameters on the appearance of cracks,holes and other defects in the forming process through optical microscope metallographic quality observation,and gradually optimized the process parameters.At last,mechanical and damping performance test specimens was fabricated by the optimized SLM process parameters for mechanical and damping performance tests.The SLM-ed M2052 alloy was subjected to different heat treatments including solid solution,aging,solution+aging.The metallographic observation,XRD,SEM,tensile impact mechanical properties and damping performance of different states were compared with the as-fabricated.The results showed that the SLM-ed materials subjected to different heat treatments had larger damping capacities at room temperature,and showed a strong damping strain amplitude effect and temperature effect,which gradually increased with the increase of strain amplitude,with the rise of temperature but first slowly increases after reaching the damping peak.It was found that the SLM-ed had better tensile strength and low-frequency damping performance,but the plasticity was poorest;The solid solution treatment could significantly improve the impact toughness of the materials since there were more twinning structures after solid solution treatment.Aging treatment could induce lattice distortion and precipitate a certain?-Mn phase,which would further improve the damping properties and damping peak temperature of the materials.Comprehensive comparison found that SLM forming M2052 alloy with solid solution and aging heat treatment has better comprehensive mechanical properties and good damping performance.Which attained503Mpa tensile strength?322.5MPa yield strength and 17J impact energy at room temperature,and the damping peak temperature is 64?in which the loss tangent tan?is 0.0426 at the strain amplitude of 5×10-4 and the frequency of 1Hz.In addition,there were wide high damping temperature interval,the highest temperature at which the damping loss tangent tan?value exceeding 0.04 could reach to 147?. |
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