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排序方式: 共有265条查询结果,搜索用时 15 毫秒
1.
自主创新发展超高强度钢 总被引:4,自引:1,他引:3
经总结有关钢的显微组织与力学性能之间的关系,以及超高强度钢发展历史的文献,作出超高强度组织、成分和热处理设计.含<0.5wt%C,(1~2)%Si,低Mn(Ni)及碳化物形成元素的钢,如0.48C-1.19Mn-1.18Si-0.95Ni-0.2Nb-0.2Mo(wt%)钢,经淬火-碳分配-回火(Q-P-T)新热处理工艺,具抗拉强度>2000MPa,并总伸长率>10%的性能,且价格低廉.含较低碳的Q-P-T钢也显示良好的综合性能. 相似文献
2.
纳米材料的马氏体相变 总被引:2,自引:0,他引:2
简述了纳米材料的定义、制备、结构、性能和应用。总结了马氏体相变的尺寸效应。概括了近十年来,纳米材料的马氏体相变和热力学研究的最新结果。 相似文献
3.
The relationship between the electronic structure of FCC phase in Fe-Mn-Si alloy and its stability has been studied by using the discrete variational method based on the first principle. The reason why Mn and Si elements have different influences on the stacking fault energy may be related to the electron concentration ( e/a). Si reduces the hole number of 3d band while Mn is rather complicated . The binding energy has been calculated and the experimental results that martensite start temperature (Ms) varies with Si and Mn are explained. When the external stress is exerted in three directions, the electronic structure, the total density of states, the energy gap at Fermi energy level( EF) and the energy degeneracy will change into other states. When the different external stresses are exerted in one direction, 3d or 4s orbital occupations of the central atom decrease, the partial density of states seems to be thinner and its peak increases at EF, the bond orbit shrinks in the direction of the external st 相似文献
4.
Temperature has great influence on the stacking fault energy (SFE). Both SFE and dr0/ d T for Fe-based alloys containing substitutional or interstitial atoms increase with increasing tempera-ture. Based on the thermodynamic model of SFE, the equation dr0/dT=drcn/dT+drseg/dT+drMG/dT and thoseexpressions for three items involved are established. The calculated dr0/dT is generally consistent with the experimental. The influence of chemical free energy on the temperature dependence of SFE is almost constant, and is obviously stronger than that of magnetic and segregation contributions. The magnetic transition and the segregation of alloying elements at stacking faults cause a decrease in SFE of the alloys when temperature increases; that is, drMG/dT<0 and dyseg/dT<0. Meanwhile, such an influence decreases with increasing temperature, except for the drseg/d 7 of Fe-Mn-Si alloys. With these results, the experimenal phenomena that the SFE of Fe-based alloys is not zero at the thermo-dynamically equilibrated tem 相似文献
5.
条状马氏体形态对钢力学性质的影响 总被引:5,自引:0,他引:5
总结了有关条状马氏体形态对钢力学性质(主要为强度)影响的文献。由于马氏体束比领域小很多,且也具有高角度位向差界面,一般束宽为决定条状马氏体强韧性的主要因素。但当马氏体条宽在几十nm级时,条宽将对钢的强度和韧性作更大贡献。 相似文献
6.
贝氏体相变研究的进展 总被引:1,自引:1,他引:0
徐祖耀 《兵器材料科学与工程》1989,(8):13-14
本文对贝氏体相变研究的进展作概括的综述,包括钢中贝氏体的形态、贝氏体的定义,从动力学、晶体学、形状改变、热力学及奥氏体强度和扩散系数对相变的影响探讨贝氏体相变的机制;有色合金贝氏体的形态和结构、从贝氏体形成时成分改变、晶体学及热力学判断贝氏体相变的机制;简介贝氏体预相变和贝氏体的应用。 相似文献
7.
Based on the experimental result that Crand C segregated on the prior grain boundariesof austenite in overheated steels,causing theinheritance of fracture mode after re-austeni-tization,a thermodynamic analysis is conductedthrough the calculation of equilibrium segregationamount of Cr and C in grain boundary at 860and 1050℃ and the segregation kinetics of Cris also calculated.Thermodynamic calculationgives an evidence that the segregation of Crand C at grain boundaries may be regarded asone of the mechanisms of the fracture inheritancein overheated steels. 相似文献
8.
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10.
By means of X-ray diffraction profile analysis of three different composition Fe-Mn-Si alloys, the relationship between stacking fault probability P_(sf) with the concentrations of constituents in alloys, 1/P_(sf)=540.05 23.70×Mn wt%-138.74×Si wt%, was determined. According to the nucleation mechanism by stacking fault in this alloy,the equation between critical driving force ΔG_c and P_(sf), ΔG_c=67.487 0.1775/P_(sf)(J/mol), was made. Therefore,the relationship between critical driving force and compositions was established. Associated with the thermodynamic calculation, the M_s of fcc(γ)→hcp(ε) martensitic transformation in any suitable composition Fe-Mn-Si shape memory alloys can be predicted and results seem reasonable as compared with some experimental data. 相似文献