Lately, cardiovascular diseases are becoming a critical issue to human health and patients suffer from such a disease tend to be increasing throughout the world due to the changes in lifestyle. As the remedies to card...Lately, cardiovascular diseases are becoming a critical issue to human health and patients suffer from such a disease tend to be increasing throughout the world due to the changes in lifestyle. As the remedies to cardiovascular diseases, a coronary artery bypass graft surgery （CABG） and a stent implantation have been widely used. In order to achieve successful results through these treatments, a stent must fulfill the certain conditions with its design and mechanical properties. A stent must have sufficient stiffness to secure the strength of narrowed blood vessel and sufficient fatigue strength against the pulsatory motion of the blood vessel. Also its high flexibility is mandatory not to damage the vessel wall while it is being transferred to the lesion through the blood vessel. A design of stent has considerable influence upon the performance of stent. Thickness, curvature and connection method of strut are main variable factors in stent design.展开更多
Thermal fatigue and high temperature wear are the two principle failure mechanisms for thixoforming dies. Samples of Inconel 617 and Stellite 6 alloys were submitted to thermal cycling under conditions which approxima...Thermal fatigue and high temperature wear are the two principle failure mechanisms for thixoforming dies. Samples of Inconel 617 and Stellite 6 alloys were submitted to thermal cycling under conditions which approximate thixoforming of steels and to sliding wear tests at 750 ℃. The experimental results thus obtained were compared with those of the X32CrMoV33 hot work tool steel. The Inconel 617 and Stellite 6 samples are much more resistant to oxidation and to softening than the hot work tool steel, providing a superior resistance to thermal fatigue cracking. The wear resistance of the Inconel 617 and Stellite 6 alloys at 750 ℃ is also markedly superior. The adhesive oxides growing slowly on Inconel 617 and Stellite 6 alloys sustain the wear action without spalling and are claimed to be responsible for the superior wear resistance of these alloys at 750 ℃.展开更多
文摘Lately, cardiovascular diseases are becoming a critical issue to human health and patients suffer from such a disease tend to be increasing throughout the world due to the changes in lifestyle. As the remedies to cardiovascular diseases, a coronary artery bypass graft surgery （CABG） and a stent implantation have been widely used. In order to achieve successful results through these treatments, a stent must fulfill the certain conditions with its design and mechanical properties. A stent must have sufficient stiffness to secure the strength of narrowed blood vessel and sufficient fatigue strength against the pulsatory motion of the blood vessel. Also its high flexibility is mandatory not to damage the vessel wall while it is being transferred to the lesion through the blood vessel. A design of stent has considerable influence upon the performance of stent. Thickness, curvature and connection method of strut are main variable factors in stent design.
文摘Thermal fatigue and high temperature wear are the two principle failure mechanisms for thixoforming dies. Samples of Inconel 617 and Stellite 6 alloys were submitted to thermal cycling under conditions which approximate thixoforming of steels and to sliding wear tests at 750 ℃. The experimental results thus obtained were compared with those of the X32CrMoV33 hot work tool steel. The Inconel 617 and Stellite 6 samples are much more resistant to oxidation and to softening than the hot work tool steel, providing a superior resistance to thermal fatigue cracking. The wear resistance of the Inconel 617 and Stellite 6 alloys at 750 ℃ is also markedly superior. The adhesive oxides growing slowly on Inconel 617 and Stellite 6 alloys sustain the wear action without spalling and are claimed to be responsible for the superior wear resistance of these alloys at 750 ℃.
