| Cu-Ni-Mn-P alloy,as a new type of aging quaternary copper alloy,has excellent properties such as high strength and high elasticity.It is widely used in the preparation of precision instruments as elastic components and various electrical springs for relays.Contact springs,various plug-in parts,diaphragms,diaphragms and spring tubes,etc.At present,there are few studies on Cu-Ni-Mn-P alloys,mainly focusing on the types and structures of precipitated phases.However,there is no comprehensive and systematic study on the influence and effect of the content of Ni and Mn added in the alloy on the structure and properties of the alloy,which limits the further development and use of the alloy.In this paper,on the basis of the atomic ratio Ni:Mn:P = 1:1:1(NMP111 alloy)in the Cu-Ni-Mn-P alloy,the same atomic weight of Ni and Mn elements are added to prepare the atomic ratio Ni:Mn:P = 2:1:1(NMP211 alloy)and Ni:Mn:P = 1:2:1(NMP121 alloy).Through the "casting-hot rolling-solid solution-aging" and "casting-hot rolling-solid solution-cold rolling-aging" process,the use of modern analysis and detection technology to characterize the alloy in the as-cast,hot-rolled,solid solution and aging.The changes in hardness,electrical conductivity and microstructure of the state of the alloy,and then further study and analyze the influence law and mechanism of the addition of Ni and Mn elements on the structure and properties of the alloy.The high-temperature softening behavior of the three-combination gold was studied,and the influence of Ni and Mn on the hightemperature softening behavior of the alloy was analyzed.The results of the study are as follows:(1)In the "casting-hot rolling-solid solution-aging" process,the addition of Ni and Mn can effectively reduce the dendrites in the alloy and improve the as-cast structure of the alloy.All three combination golds aged at 500°C show obvious age hardening effect.Compared with NMP211 alloy,NMP121 alloy has better peak hardness,but the conductivity is significantly deteriorated.The TEM observation shows that the precipitated phases of the triple combination gold are all Ni P phases of the monoclinic system.Through the calculation of the resistivity of the three combinations of gold,it is found that the most damage to the alloy conductivity is the solute element remaining in the matrix,and the Mn element can reduce the damage of the alloy conductivity by diffusing from the matrix into the precipitated phase.Through the calculation of the strength of these three combinations of gold,it is found that the precipitation strengthening effect of the precipitated phase is the largest contribution to the yield strength of the alloy.(2)In the "casting-hot rolling-solution-cold rolling-aging" process,the peak hardness of the NMP211 alloy is higher than that of the NMP121 alloy and reaches 228 HV during the aging process at 450? after 70% cold deformation.Through the peak aging EBSD data analysis of these three alloys,it can be seen that the addition of Ni can inhibit the recrystallization behavior of the alloy during peak aging,thereby improving the softening resistance of the NMP211 alloy and making it have a higher peak hardness.(3)The high temperature softening test of the three groups of peak-aged alloys after cold rolling shows that the softening temperature of NMP111 alloy is 505 ?,and the addition of Mn can increase the softening temperature of NMP121 alloy,and its value is 530 ?.It is found that the increase of the softening resistance temperature of NMP121 alloy and the addition of Mn element inhibit the nucleation and growth of the recrystallized grains of the alloy and the coarsening of the precipitated phases. |
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