Effects of laser pulse energy on surface microstructure and mechanical properties of high carbon steel
来源期刊：中南大学学报(英文版)2015年第12期
论文作者：XIONG Yi HE Tian-tian LI Peng-yan CHEN Lu-fei REN Feng-zhang Alex A. Volinsky
文章页码：4515 - 4520
Key words：pearlitic steel; laser shock processing; microstructure; microhardness; residual stress
Abstract: Surface microstructure and mechanical properties of pearlitic Fe–0.8%C (mass fraction) steel after laser shock processing (LSP) with different laser pulse energies were investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD) and microhardness measurements. After LSP, the cementite lamellae were bent, kinked and broken into particles. Fragmentation and dissolution of the cementite lamellae were enhanced by increasing the laser pulse energy. Due to the dissolution of carbon atoms in the ferritic matrix, the lattice parameter of α-Fe increased. The grain size of the surface ferrite was refined, and the microstructure changed from lamellae to ultrafine micro-duplex structure (ferrite (α)+cementite (θ)) with higher laser pulse energy, accompanied by the residual stress and microhardness increase.
XIONG Yi(熊毅)1, 2, HE Tian-tian(贺甜甜)3, LI Peng-yan(李鹏燕)1, CHEN Lu-fei(陈路飞)1, REN Feng-zhang(任凤章)1, 2, Alex A. Volinsky4
(1. School of Materials Science and Engineering, Henan University of Science and Technology,
Luoyang 471023, China;
2. Collaborative Innovation Center of Nonferrous Metals, Luoyang 471023, China;
3. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;
4. Department of Mechanical Engineering, University of South Florida, Tampa FL 33620, USA)
Abstract:Surface microstructure and mechanical properties of pearlitic Fe–0.8%C (mass fraction) steel after laser shock processing (LSP) with different laser pulse energies were investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD) and microhardness measurements. After LSP, the cementite lamellae were bent, kinked and broken into particles. Fragmentation and dissolution of the cementite lamellae were enhanced by increasing the laser pulse energy. Due to the dissolution of carbon atoms in the ferritic matrix, the lattice parameter of α-Fe increased. The grain size of the surface ferrite was refined, and the microstructure changed from lamellae to ultrafine micro-duplex structure (ferrite (α)+cementite (θ)) with higher laser pulse energy, accompanied by the residual stress and microhardness increase.
Key words:pearlitic steel; laser shock processing; microstructure; microhardness; residual stress
