Contact reaction brazing process for connecting TZM alloy and graphite through pure zirconium layer

Abstract

The invention relates to the technical field of brazing, and discloses a contact reaction brazing process for connecting TZM alloy and graphite through a pure zirconium layer, which comprises the following steps: step 1, taking TZM alloy, graphite and Zr foil to be welded, polishing the surfaces to be welded by using abrasive paper, and ultrasonically cleaning the sample in an organic solution for 30 minutes; and 2, grooving the surface of the graphite in the step 1, and then sequentially putting Zr foil and TZM alloy into the grooves in the surface of the graphite so as to prevent the sample from being misplaced and prevent brazing filler metal from flowing out. And (3) the workpiece assembled in the step (2) is put into a furnace cavity of a vacuum air pressure sintering furnace, the furnace cavity is vacuumized to be lower than 1 * 10 <-3 > Pa, then argon is filled into the furnace cavity to reach the set pressure, and the temperature is increased to 1000 DEG C from 20 DEG C at the speed of 50 DEG C / min. According to the method, the requirement for the smoothness of the welding surface can be lowered by adding the zirconium middle layer, and the welding surface can be subjected to various treatments such as polishing, sand blasting and machining according to the requirements so as to increase the mechanical occlusal force.

Description

technical field [0001] The invention relates to the technical field of brazing, in particular to a contact reaction brazing process for connecting a TZM alloy and graphite with a pure zirconium layer. Background technique [0002] At present, TZM (molybdenum-titanium-zirconium) alloys have attracted extensive attention in many high-temperature applications due to their high melting point (2620 °C), low expansion coefficient, good mechanical properties at high temperatures, and excellent electrical and thermal conductivity, such as nuclear energy. , aerospace and X-ray targets and other fields. However, due to the high density, difficulty in processing and welding of TZM alloys, its further widespread application is limited. In addition, due to its low density, high wear resistance, excellent thermal conductivity, good ablation resistance, thermal shock resistance, fatigue resistance, corrosion resistance and other characteristics, graphite is also widely used in aerospace, ...

AI Technical Summary

Problems solved by technology

For mechanical connection, it is necessary to pre-drill holes in the graphite workpiece, which is easy to cause stress concentration and peeling, and due to the low strength of graphite, these lead to low joint strength of mechanical connection, which is difficult to use as a structural material

For adhesive connection, the high porosity of graphite allows the liquid adhesive to penetrate the surface and improve the mechanical strength of the joint, but the adhesive connection faces problems such as failure at high temperature, making it impossible to use in high temperature environments

Diffusion welding is a more reliable process for connecting graphite and TZM alloys, but this welding method needs to provide high temperature and high pressure environment, long welding time, and high quality requirements for the welding surface

For example, in the patent document whose publication number is CN109048030A, an expensive spark plasma sintering furnace is used for diffusion welding, and the configuration cost is high.

In the patent document whose publication number is CN105397264A, a vacuum hot-press furnace is used to carry out direct diffusion welding of TZM alloy and graphite, but this method has higher requirements on the smoothness of the welding surface of the workpiece, and the required pressure is also larger and longer, time-consuming strenuous

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