TEM OBSERVATION OF NUCLEATION AND GROWTH OF BORIDES DURING BORONIZATION OF STEEL 20 AND INFLUENCE OF PRIOR DEFORMATION
20钢渗硼过程中硼化物形核和生长的TEM观察及室温形变的影响

TEM observation in situ on the single-side thinned specimens wasmade of the nucleation and growth of borides during boronization of steel 20 andthe influence of prior room temperature deformation. The results of X-ray diffrac-tion and electron probe microstructure analysis show that only Fe_2B formed inthe surface layer of specimens at the beginning of boronization; the atomic concen-tration of B in the surface layer increased with the increase of deformation mon-otonously; and the segregation of B atoms in the dislocation cells hindered the re-covery and recrystallization of the deformed structure of the matrix and accelara-ted the nucleation and growth of borides in the surface layer.