| With the rapid development of the machine manufacturing industry,people's lives have become rich and colorful,but the vibration and noise caused by it have also seriously affected people's health.Therefore,the development of damping materials has become an essential task.Fe-Mn alloy has attracted attention at home and abroad because of its advantages such as low cost and high strength.In this experiment,the dynamic mechanical analyzer DMA Q800 was used to measure damping capacity.OM,SEM-EBSD,TEM,XRD and other testing methods were used to analyze microstructure and properties of the alloy in different states.Phase transformation points of the alloy was measured by dynamic transformation instrument,and the corrosion resistance of the alloy was analyzed by simulated seawater experiments,the microhardness of the alloy was measured at the same time.The following experimental results were obtained:(1)The microstructure and properties of Fe-19Mn and Fe-19Mn-8Cr alloys after the same solution treatment were compared.With the addition of Cr,the probability of stacking faults and the Ms point decreased,the volume of ? martensite and damping capacity were reduced,and the corrosion resistance of the alloy was greatly improved.The microhardness of the alloy hardly changed,that is,the effect of solid solution strengthening was not obvious.(2)The influences of hot rolling and cold rolling deformation on the microstructure and properties of Fe-19Mn-8Cr alloy were analyzed.After hot rolling deformation of the alloy,the content of s martensite in the microstructure was low,and the morphology was not in the form of lath,then damping capacity decreased.At the same time,the corrosion resistance of the alloy was poor;however,,damping capacity of the alloy increased after cold rolling deformation with a small reduction ratio because a large number of ? martensite was induced due to stress.As the reduction rate continued to increase,the content of s martensite also increased,but ? martensite entangled with each other,and ?????' phase transformation occured,and a large number of dislocations were introduced,resulting in reduced damping capacity.After cold rolling deformation,the corrosion resistance and hardness of the alloy increased.(3)The effect of annealing treatment on the microstructure and properties of the alloy after the cold rolling deformation of Fe-19Mn-8Cr alloy at 70%reduction rate was analyzed.As the annealing temperature increased,the dislocations in the entangled alloy were eliminated,and the ? martensite morphology in the structure recovered into strips,increasing the ?/? interface area,thereby improving damping capacity of the alloy.When temperature was higher than 800?,the s martensite in the microstructure was coarsened,the ?/? interface area was greatly reduced,and damping capacity decreased.After annealing,the corrosion resistance and microhardness of the alloy were reduced.After the alloy was annealed and heat-cycled,the ?martensite content in the alloy increased and the size becomes finer,so damping capacity of the alloy was further improved.(4)The comparison of damping capacity of Fe-19Mn-8Cr alloy after annealing with water,oil and air was compared and analyzed.After oil cooling,the grain size and content of ?martensite in the alloy was similar to that after water cooling,but the concentration of quench vacancies in the structure was relatively small,compared with air cooling,the grain size of ?martensite was more fine and the content was more,so damping capacity of the alloy after oil cooling was the best.(5)The effects of different aging time and temperature on damping capacity of Fe-19Mn-8Cr were analyzed.When aging time was 2h,damping capacity of the alloy decreased with the increasing aging temperature.And aging time was 40 min.As aging temperature increased,damping capacity of the alloy increased first and then decreased.The changes in the microstructure and damping capacity of Fe-19Mn and Fe-19Mn-8Cr alloys after the same aging treatment were compared and analyzed.The results showed that,after aging treatment,the effect of improving damping capacity of the alloy was even more pronounced due to more ? martensite content in Fe-19Mn alloy. |
PDF Full Text Request