The effects of laser hardening parameters such as beam power, beam diameter and scanning rate on microstructure and hardness of 9CrSi steel were investigated. The microstructure of the surface layer of 9CrSi steel was...The effects of laser hardening parameters such as beam power, beam diameter and scanning rate on microstructure and hardness of 9CrSi steel were investigated. The microstructure of the surface layer of 9CrSi steel was changed from pearlite to martensite, retained austenite and carbide by laser hardening. The depth of the hardened layer increased with increasing laser energy density and the surface hardeness increased by 3-5 times as high as the untreated steel. The laser hardened surface had good wear resistance due to martensite and carbide in the surface layer. The wear mode at low speed was abrasive, while the wear mode at high speed was adhesive.展开更多
The quench transfomation in a Ti-10V-2Fe-3Al near B-titanium alloy was studied by means of X-ray diffraction, transmission electron microscopy, and optical micyoscopy. The quenching temperatures were above and below t...The quench transfomation in a Ti-10V-2Fe-3Al near B-titanium alloy was studied by means of X-ray diffraction, transmission electron microscopy, and optical micyoscopy. The quenching temperatures were above and below the β transus temperature. The phase constitutions of specimens quenched from various solution temperatures were identified and the phase morphologies were examined. In addition, the relationship between phase lattice parameters and quenching tempera- tures was given for α, β and α ^(11) phases. This alloy has a tendency of precipitation of athermal ω phase and formation of stress induced α^(11) mar- tensite from β phase during quenching. Quenched from the temperatures above the β transus tem- perature, the alloy mainly consists of β phase, a small amount of α^(11) martensite and athemal ω phase aye also present in the alloy. After quenching from the temperatures below the β transus temperature, the α phase appeays in the alloy in addition to the phases mentioned above.展开更多
文摘The effects of laser hardening parameters such as beam power, beam diameter and scanning rate on microstructure and hardness of 9CrSi steel were investigated. The microstructure of the surface layer of 9CrSi steel was changed from pearlite to martensite, retained austenite and carbide by laser hardening. The depth of the hardened layer increased with increasing laser energy density and the surface hardeness increased by 3-5 times as high as the untreated steel. The laser hardened surface had good wear resistance due to martensite and carbide in the surface layer. The wear mode at low speed was abrasive, while the wear mode at high speed was adhesive.
文摘The quench transfomation in a Ti-10V-2Fe-3Al near B-titanium alloy was studied by means of X-ray diffraction, transmission electron microscopy, and optical micyoscopy. The quenching temperatures were above and below the β transus temperature. The phase constitutions of specimens quenched from various solution temperatures were identified and the phase morphologies were examined. In addition, the relationship between phase lattice parameters and quenching tempera- tures was given for α, β and α ^(11) phases. This alloy has a tendency of precipitation of athermal ω phase and formation of stress induced α^(11) mar- tensite from β phase during quenching. Quenched from the temperatures above the β transus tem- perature, the alloy mainly consists of β phase, a small amount of α^(11) martensite and athemal ω phase aye also present in the alloy. After quenching from the temperatures below the β transus temperature, the α phase appeays in the alloy in addition to the phases mentioned above.
