34 results about "Stress induced martensite" patented technology

An electrosurgical apparatus for coagulating tissue includes an elongated flexible tube having a proximal end, a distal end and a source for supplying pressurized ionizable gas to the proximal end of the tube. The apparatus also includes a hollow sleeve made from a shape memory alloy having a generally curved austenite state and displaying stress-induced martensite behavior. The hollow sleeve is restrained in a deformed stress-induced martensite configuration within the tube and partial extension of a portion of the hollow sleeve from the tube transforms the portion of the sleeve from the deformed configuration to the generally curved austenite configuration such that the gas is directed transversely at the tissue. An electrode ionizes the gas in the region between the sleeve and the tissue. Other embodiments of the present disclosure also include a wire connected to the distal end of the tube which movable from a first postion wherein the tube is disposed in a generally rectilinear, parallel fashion relative to the tissue to a second retracted position wherein the distal end of the tube flexes at an angle to direct the gas towards the tissue. Still other embodiments of the present disclosure include a corona electrode for inducing ignition of the gas.

A process for assembling a medical device made from a nickel-titanium alloy for use in a mammalian body while avoiding the formation of stress-induced martensite and a medical device used in combination with a delivery system for deployment into the mammalian body are disclosed. By heating the nickel-titanium alloy of the medical device to a temperature above Md, and deforming and installing the device into a delivery system or holding capsule, it is possible to avoid the formation of stress-induced martensite in the stent, which stays in the austenitic phase throughout.

An electrosurgical apparatus for coagulating tissue includes an elongated flexible tube having a proximal end, a distal end and a source for supplying pressurized ionizable gas to the proximal end of the tube. The apparatus also includes a hollow sleeve made from a shape memory alloy having a generally curved austenite state and displaying stress-induced martensite behavior. The hollow sleeve is restrained in a deformed stress-induced martensite configuration within the tube and partial extension of a portion of the hollow sleeve from the tube transforms the portion of the sleeve from the deformed configuration to the generally curved austenite configuration such that the gas is directed transversely at the tissue. An electrode ionizes the gas in the region between the sleeve and the tissue. Other embodiments of the present disclosure also include a wire connected to the distal end of the tube which movable from a first postion wherein the tube is disposed in a generally rectilinear, parallel fashion relative to the tissue to a second retracted position wherein the distal end of the tube flexes at an angle to direct the gas towards the tissue. Still other embodiments of the present disclosure include a corona electrode for inducing ignition of the gas.

The invention discloses a method for manufacturing shear-type phase change crack resistance by laser additive manufacturing, which includes adopting laser additive manufacturing technology, and using high-entropy alloy powder with FCC→HCP martensitic phase transition as a special powder for additive manufacturing; Dry the metal powder in a vacuum drying oven for 12 hours at a drying temperature of 120°C; perform additive manufacturing printing on the dried high-entropy alloy powder, and the printing parameters are: laser power 400W; scanning speed 800-1600mm / s ; The scanning distance is 0.09mm; the powder coating thickness is 0.03mm; the substrate preheating temperature is 100°C. The invention solves the problem of metallurgical defects such as thermal crack deformation caused by high temperature and high stress gradient in the molten pool in the traditional laser additive manufacturing process. And on the basis of this research, the idea of ​​stress-induced martensitic transformation to suppress hot cracks in additive manufacturing alloys is extended to other additive manufacturing alloy systems, providing a new method for additive manufacturing of crack-free alloys.

The invention relates to a shape memory alloy blocking nut and its preparing process. The raw materials for the nut comprise the following components(in % by weight): C 0.01-0.05, Mn 15.0-17.0, Si 4.8-5.2, Cr8.5-9.5, Ni 6.5-7.5, P 0.01-0.03, S 0.01-0.02, N 0.03-0.05, and Fe 60.65-65.05. The preparing process comprises: (1) preparing the raw materials and rolling to obtain the iron-base shape memory alloy rod stocks with outside hexagon strip and inner circular hole; (2) solution treatment for the rod stocks: keeping the temperature of 950K. to 1150K. for 30 min to 60 min; (3) shape memory training for the rod stocks; (4) cutting the rod stocks to nut blanks, and processing the inner circular hole according to the given size of 94% to 96%; (5) reaming the nut to given size for completing the stress induced martensitic transformation of the nut; (6) fine machining for the internal thread; (7) pre-tightening the nut according to the estimated force moment, keeping the temperature of 500K to 800K for 15min to 45min, and carrying out the annealing treatment.