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Grain Boundary Martensite Formation and Tempering Brittleness at Low Temperature of Steels

Author: LiuShiFeng
Tutor: WangRuiXiang
School: Hebei University of Technology
Course: Materials Science
Keywords: Martensite Temper brittleness Grain boundary Segregation
CLC: TG142.2
Type: Master's thesis
Year: 2009
Downloads: 182
Quote: 0
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Abstract


In this study, the industrial 65Mn CrWMn , 50GrMn 5GrMnMo 42GrMo martensite formation and temper brittleness . Found that the first six steel quenching preferentially at the grain boundaries to form a large plate martensite the temper brittleness larger ; the Mo steel grain boundary martensite obvious , the temper brittleness corresponding small . These results indicate that the grain boundary plate martensite may be one of the reasons why steel temper brittleness of the of 65Mn, CrWMn and 50GrMn steel impact experiments to compare the two kinds of heat treatment process of steel temper brittleness . The experimental results show that : isothermal quenching so that the grain boundaries of steel to give priority to generate lower bainite Replaced plate martensite grain boundary of the grain boundary , by tempering steel tempering brittleness relatively small . Grain boundary martensite morphology observation , analysis of a the quenching priority plate martensite formed during tempering impact on the organization , in particular, played a catalytic C diffusion and impurity elements P segregation the role of increased temper brittleness of steel . Sub-structure of the grain boundary martensite was observed by transmission electron microscopy , and its sub-structures both twinning dislocations , we think : plate martensite nucleation at the austenite grain boundaries , grain boundary bit wrong may martensite nucleation and growth process in the lattice constant shear dislocation source , and easily along the crystal face growing up , so when the the martensite piece grew exist within many of dislocation structure .

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metallic materials > Steel > A variety of steel products : Organization distinguish
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