In order to improve the mechanical properties of powder metallurgy （P/M） ferrite-pearlite steel, a dual phase （DP） ferrite-martensite steel was produced through intercritical annealing of sintered P/M preforms. Mi...In order to improve the mechanical properties of powder metallurgy （P/M） ferrite-pearlite steel, a dual phase （DP） ferrite-martensite steel was produced through intercritical annealing of sintered P/M preforms. Mi-crostructures of the sintered and DP steels were examined with optical, scanning and transmission electron microscopes. Mechanical properties were evaluated through hardness measurements and compression tests. Microstructural studies revealed that sintered steel contained polygonal ferrite-pearlite while the DP steel contained polygonal, lath and acicular ferrite along with lath-type martensite as microstructural constituents. In DP steels, with increasing mean preform density, the microstructure contained fine and continuous network of martensite colonies with minimum porosity. The work hardening rate vs plastic strain plots （Jaoul-Crussard analysis） of both the steels revealed typical three stage deformation behaviour for low and high mean preform densities. Compression tests revealed that, DP P/M steel displayed higher strength-plasticity combination than the sintered steel.展开更多
Modelling has become a more and more valuable tool in the design, control and development of steel processing. Empirical regression equations, physically based approachs, artificial neural networks and hybrid models a...Modelling has become a more and more valuable tool in the design, control and development of steel processing. Empirical regression equations, physically based approachs, artificial neural networks and hybrid models are being theied in computer modelling. In all cases, relevant data are necessary, which can be most economically obtained by physical simulation. Physical simulation with a Gleeble simulator has been used in a large number of tasks at the University of Oulu for ten years in cooperotion with the Finnish metals industry. Some examples of these will be described and discussed below, such as the optimization of the recrystallization controlled rolling process, the improvement of the hot strength model for the control of coiling tension and the optimization of continuous strip annealing schedules.Finally,brief remarks will be then on a couple of projects now under way.展开更多
The“color superiority effect”was confirmed by the research of color on forgetting,which showed that proactive interference(PI)has less impact on colored items than gray ones.Color could directly affect the buildup o...The“color superiority effect”was confirmed by the research of color on forgetting,which showed that proactive interference(PI)has less impact on colored items than gray ones.Color could directly affect the buildup of PI,leading to reduced levels of interference,or controlled processes that resolve PI.However,the effects of red and green on memory were inconsistent.Using Recent-Probes task,the current study explored how the red and green color influenced to the buildup phase(i.e.,200ms after the onset of probe)and resolution phase(i.e.800ms after the onset of probe)of PI.Results revealed that the reaction times of green words were significantly shorter than the red words under 200ms.There were no significant differences between the red and green words under 500ms and 800ms.It indicated that green might shortened the reaction times for the PI buildup,while red prolonged it.However,on the resolution phase of PI,green words were less effective than red words.These findings offered some new information for the underlying mechanisms that modulate the interactions between color and memory.展开更多
文摘In order to improve the mechanical properties of powder metallurgy （P/M） ferrite-pearlite steel, a dual phase （DP） ferrite-martensite steel was produced through intercritical annealing of sintered P/M preforms. Mi-crostructures of the sintered and DP steels were examined with optical, scanning and transmission electron microscopes. Mechanical properties were evaluated through hardness measurements and compression tests. Microstructural studies revealed that sintered steel contained polygonal ferrite-pearlite while the DP steel contained polygonal, lath and acicular ferrite along with lath-type martensite as microstructural constituents. In DP steels, with increasing mean preform density, the microstructure contained fine and continuous network of martensite colonies with minimum porosity. The work hardening rate vs plastic strain plots （Jaoul-Crussard analysis） of both the steels revealed typical three stage deformation behaviour for low and high mean preform densities. Compression tests revealed that, DP P/M steel displayed higher strength-plasticity combination than the sintered steel.
文摘Modelling has become a more and more valuable tool in the design, control and development of steel processing. Empirical regression equations, physically based approachs, artificial neural networks and hybrid models are being theied in computer modelling. In all cases, relevant data are necessary, which can be most economically obtained by physical simulation. Physical simulation with a Gleeble simulator has been used in a large number of tasks at the University of Oulu for ten years in cooperotion with the Finnish metals industry. Some examples of these will be described and discussed below, such as the optimization of the recrystallization controlled rolling process, the improvement of the hot strength model for the control of coiling tension and the optimization of continuous strip annealing schedules.Finally,brief remarks will be then on a couple of projects now under way.
文摘The“color superiority effect”was confirmed by the research of color on forgetting,which showed that proactive interference(PI)has less impact on colored items than gray ones.Color could directly affect the buildup of PI,leading to reduced levels of interference,or controlled processes that resolve PI.However,the effects of red and green on memory were inconsistent.Using Recent-Probes task,the current study explored how the red and green color influenced to the buildup phase(i.e.,200ms after the onset of probe)and resolution phase(i.e.800ms after the onset of probe)of PI.Results revealed that the reaction times of green words were significantly shorter than the red words under 200ms.There were no significant differences between the red and green words under 500ms and 800ms.It indicated that green might shortened the reaction times for the PI buildup,while red prolonged it.However,on the resolution phase of PI,green words were less effective than red words.These findings offered some new information for the underlying mechanisms that modulate the interactions between color and memory.
