Rupture and tensile properties of K17 before and after thermal exposure in vacuum,air and hot corrosion environments have been investigated.The results show that vacuum exposure es- sentially does not affect the ruptu...Rupture and tensile properties of K17 before and after thermal exposure in vacuum,air and hot corrosion environments have been investigated.The results show that vacuum exposure es- sentially does not affect the rupture lives but it results in the decrease of high temperature ten- sile strength and increases of rupture and high temperature tensile ductilities;air or hot corro- sion environmental exposure results in the degradation of alloy:severely reduce the rupture and high temperature tensile properties,hot corrosion environmental exposure being more harmful.The former causes grain boundary oxidation and depletion of Cr,and the later makes the sulphurization at grain boundaries.This results in the concentration of S and de- pletion of Cr at grain boundaries and,consequently,weakens the grain boundaries.展开更多
Using free bending method,the residual stress of the Ti(CN)coating on alloy Nb-752 was measured to be 2-3 GPa of which the thermal stress cmounts to 10—20%.An analysis on coating/substrate interface stress state show...Using free bending method,the residual stress of the Ti(CN)coating on alloy Nb-752 was measured to be 2-3 GPa of which the thermal stress cmounts to 10—20%.An analysis on coating/substrate interface stress state shows that the share stress at it is about O.1—0.2 GPa.The demage mode of the coating under external loading was proposed in terms of the amount and the direction of loading.展开更多
文摘Rupture and tensile properties of K17 before and after thermal exposure in vacuum,air and hot corrosion environments have been investigated.The results show that vacuum exposure es- sentially does not affect the rupture lives but it results in the decrease of high temperature ten- sile strength and increases of rupture and high temperature tensile ductilities;air or hot corro- sion environmental exposure results in the degradation of alloy:severely reduce the rupture and high temperature tensile properties,hot corrosion environmental exposure being more harmful.The former causes grain boundary oxidation and depletion of Cr,and the later makes the sulphurization at grain boundaries.This results in the concentration of S and de- pletion of Cr at grain boundaries and,consequently,weakens the grain boundaries.
文摘Using free bending method,the residual stress of the Ti(CN)coating on alloy Nb-752 was measured to be 2-3 GPa of which the thermal stress cmounts to 10—20%.An analysis on coating/substrate interface stress state shows that the share stress at it is about O.1—0.2 GPa.The demage mode of the coating under external loading was proposed in terms of the amount and the direction of loading.
