形变过程中TRIP效应的相变热动态研究
|
摘要
采用拉伸与测温试验同时进行的方法,将应力应变曲线与热能曲线相结合,动态研究热轧TRIP钢拉伸过程中的相变热.研究表明:热轧TRIP钢在拉伸过程中材料增加的热能由部分转变的塑性功和马氏体相变热组成,因此,拉伸过程中实际测得的试样热能高于由塑性功转变的热能.利用平均综合热能损失系数对低速拉伸的TRIP钢的热能进行补充,通过计算与推导,证实了试样在刚进入塑性变形时,一定数量的较不稳定残余奥氏体首先集中发生马氏体相变,随着应变的进一步加大,剩余的较稳定的残余奥氏体根据其稳定情况发生马氏体相变的数量逐渐减少,在试样均匀延伸结束前绝大部分残余奥氏体已转变为马氏体.结合相变热变化可动态描述热轧TRIP钢形变过程中马氏体相变的情况.
During tensile and temperature tests,the latent heat of hot-rolled TRIP steel was dynamically investigated by observing the stress-strain and thermal curves.The results indicated that during the tensile test,the hot-rolled TRIP steel increased the thermal energy,which originated from the partial transformation of plastic work and martensitic transformation.Therefore,the actual heat of the measured sample was higher than that converted by plastic work.During the low speed tensile test,the thermal energy of the TRIP steel was supplemented by the average integrated heat loss coefficient.Through calculation and deduction,it was confirmed that a certain amount of the unstable residual austenite first became martensite,when the plastic deformation had just begun.As the strain increased further,the amount of the remaining,stable,retained austenite that would become martensite,decreased gradually according to its stability.Most of the retained austenite had almost become martensite before the end of the uniform elongation.During the deformation process of the hot rolled TRIP steel,the martensitic transformation could be dynamically described by the change of latent heat.
During tensile and temperature tests,the latent heat of hot-rolled TRIP steel was dynamically investigated by observing the stress-strain and thermal curves.The results indicated that during the tensile test,the hot-rolled TRIP steel increased the thermal energy,which originated from the partial transformation of plastic work and martensitic transformation.Therefore,the actual heat of the measured sample was higher than that converted by plastic work.During the low speed tensile test,the thermal energy of the TRIP steel was supplemented by the average integrated heat loss coefficient.Through calculation and deduction,it was confirmed that a certain amount of the unstable residual austenite first became martensite,when the plastic deformation had just begun.As the strain increased further,the amount of the remaining,stable,retained austenite that would become martensite,decreased gradually according to its stability.Most of the retained austenite had almost become martensite before the end of the uniform elongation.During the deformation process of the hot rolled TRIP steel,the martensitic transformation could be dynamically described by the change of latent heat.
引文
[1]Powers W F.Automotive materials in the 21st century.Adv Mater Processes,2000,157(5):38
[2]Yi H L,Xu W,Long L Z,et al.Research on microstructures and mechanical properties of hot rolled Ti-microalloyed TRIP steel.J Mater Eng,2014(12):66(衣海龙,徐薇,龙雷周,等.热轧钛微合金化TRIP钢的组织与性能研究.材料工程,2014(12):66)
[3]Girault E,Jacques P,Harlet P,et al.Metallographic methods for revealing the multiphase microstructure of TRIP-assisted steels.Mater Charact,1998,40(2):111
[4]Ray A,Dhua S K.Microstructural manifestations in color:some applications for steels.Mater Charact,1996,37(1):1
[5]Manochar P A,Kunishige K,Chandra T,et al.Continuous cooling transformation behaviour of Si--Mn and Al--Mn transformation induced plasticity steels.Mater Sci Technol,2002,18(8):856
[6]Mintz B.Hot dip galvanizing of transformation induced plasticity and other intercritically annealed steels.Int Mater Rev,2001,46(4):169
[7]Hanzaki A Z,Hodgson P D,Yue S.Hot deformation characteristics of Si-Mn TRIP steels with and without Nb microalloy additions.ISIJ Int,1995,35(3):324
[8]De A K,Speer J G,Matlock D K.Color tint-etching for multiphase steels.Adv Mater Processes,2003,161(2):27
[9]Lim T K,Axcell B P,Cotton M A.Single-phase heat transfer in the high temperature multiple porous insulation.Appl Therm Eng,2007,27(8-9):1352
[10]Hilditch T B,Speer J G,Matlock D K.Influence of low-strain deformation characteristics of high strength sheet steel on curl and springback in bend-under-tension tests.J Mater Process Technol,2007,182(1-3):84
[11]Song R,Ponge D,Raabe D.Mechanical properties of an ultrafine grained C-Mn steel processed by warm deformation and annealing.Acta Mater,2005,53(18):4881
[12]Aravas N,Kim K S,Leckie F A.On the calculation of the stored energy of cold work.J Eng Mater Technol,1990,112(4):465
[13]Lipinski P,Berveiller M,Reubrez E,et al.Transition theories of elastic-plastic deformation of metallic polycrystals.Arch Appl Mech,1995,65(5):291
[14]Rusinek A,Klepaczko J R.Experiments on heat generated during plastic deformation and stored energy for TRIP steels.Mater Des,2009,30(1):35
[15]Lee H T,Chen J C.Temperature effect induced by uniaxial tensile loading.J Mater Sci,1991,26(21):5685
[16]Li Y L.Definition and mechanical characteristics of true stressstrain.J Chongqing Univ Nat Sci Ed,2001,24(3):58(李玉兰.真应力-真应变的定义及其力学特征.重庆大学学报(自然科学版),2001,24(3):58)
[2]Yi H L,Xu W,Long L Z,et al.Research on microstructures and mechanical properties of hot rolled Ti-microalloyed TRIP steel.J Mater Eng,2014(12):66(衣海龙,徐薇,龙雷周,等.热轧钛微合金化TRIP钢的组织与性能研究.材料工程,2014(12):66)
[3]Girault E,Jacques P,Harlet P,et al.Metallographic methods for revealing the multiphase microstructure of TRIP-assisted steels.Mater Charact,1998,40(2):111
[4]Ray A,Dhua S K.Microstructural manifestations in color:some applications for steels.Mater Charact,1996,37(1):1
[5]Manochar P A,Kunishige K,Chandra T,et al.Continuous cooling transformation behaviour of Si--Mn and Al--Mn transformation induced plasticity steels.Mater Sci Technol,2002,18(8):856
[6]Mintz B.Hot dip galvanizing of transformation induced plasticity and other intercritically annealed steels.Int Mater Rev,2001,46(4):169
[7]Hanzaki A Z,Hodgson P D,Yue S.Hot deformation characteristics of Si-Mn TRIP steels with and without Nb microalloy additions.ISIJ Int,1995,35(3):324
[8]De A K,Speer J G,Matlock D K.Color tint-etching for multiphase steels.Adv Mater Processes,2003,161(2):27
[9]Lim T K,Axcell B P,Cotton M A.Single-phase heat transfer in the high temperature multiple porous insulation.Appl Therm Eng,2007,27(8-9):1352
[10]Hilditch T B,Speer J G,Matlock D K.Influence of low-strain deformation characteristics of high strength sheet steel on curl and springback in bend-under-tension tests.J Mater Process Technol,2007,182(1-3):84
[11]Song R,Ponge D,Raabe D.Mechanical properties of an ultrafine grained C-Mn steel processed by warm deformation and annealing.Acta Mater,2005,53(18):4881
[12]Aravas N,Kim K S,Leckie F A.On the calculation of the stored energy of cold work.J Eng Mater Technol,1990,112(4):465
[13]Lipinski P,Berveiller M,Reubrez E,et al.Transition theories of elastic-plastic deformation of metallic polycrystals.Arch Appl Mech,1995,65(5):291
[14]Rusinek A,Klepaczko J R.Experiments on heat generated during plastic deformation and stored energy for TRIP steels.Mater Des,2009,30(1):35
[15]Lee H T,Chen J C.Temperature effect induced by uniaxial tensile loading.J Mater Sci,1991,26(21):5685
[16]Li Y L.Definition and mechanical characteristics of true stressstrain.J Chongqing Univ Nat Sci Ed,2001,24(3):58(李玉兰.真应力-真应变的定义及其力学特征.重庆大学学报(自然科学版),2001,24(3):58)