The present disclosure provides a wire and arc additive manufacturing (WAAM) method for a magnesium alloy. The method includes the following steps: step 1: performing a WAAM process assisted by cooling and rolling; step 2: milling side and top surfaces of an additive part; step 3: performing, by friction stir processing (FSP) equipment, an FSP process on the additive part, and applying cooling and rolling to a side wall of the additive part through a cooling and rolling device during the FSP process; step 4: finish-milling the top surface of the additive part for a WAAM process in the next step; and step 5: repeating the above steps cyclically until final forming of the part is finished. The present disclosure completely breaks dendritic structures and refines grains in the WAAM process of the magnesium alloy, thereby effectively repairing defects such as pores and cracks.

A welding method for joining a first plate made of a material other than steel and a second plate made of steel includes a step of making a hole through each of the first plate and the second plate, a press-fitting step, an overlapping step, and a filling and welding step. A shaft portion of a joining assist member being solid, being made of steel, and having an outer shape with step having the shaft portion and a flange portion is press-fitted in the hole of the first plate. The first plate and the second plate is overlapped such that the shaft portion faces the hole of the second plate. The hole of the second plate is filled with a weld metal and the second plate and the joining assist member are welded.

The present disclosure provides methods for preparing an extruded product from a solid billet. The methods can include providing an as-cast billet for extrusion; applying a simultaneous rotational shear and axial extrusion force to the as-cast billet to plasticize the as-cast billet; and extruding the plasticized as-cast billet with an extrusion die to form an extruded product. Methods for preparing extruded products from billets can also include: providing a billet for extrusion; while maintaining a majority of the billet below 100° C., applying a simultaneous rotational shear and axial extrusion force to one end of the billet to plasticize the one end of the billet; and extruding the plasticized one end of the billet with an extrusion die to form an extruded product. Methods for preparing an extruded product from a billet can also include providing a billet for extrusion; applying a simultaneous rotational shear and axial extrusion force to the billet to plasticize the billet; extruding the plasticized billet with an extrusion die to form an extruded product; and artificially aging the extruded product for less than the ASTM recommended amount of time.

A component includes a magnesium alloy portion and an aluminum alloy portion. The magnesium alloy portion and the aluminum alloy portion are joined with each other via a joining portion. The aluminum alloy portion, the joining portion, and the magnesium alloy portion are covered with a chromium compound film.

A magnesium clad material 100 includes, when a cross-section thereof cut in a thickness direction thereof is observed, a Mg layer (11), a first Al layer (12) made of pure Al or an Al alloy, and a first joint (13) made of pure Cu or a Cu alloy and arranged between the Mg layer and the first Al layer, and the magnesium clad material has a 0.2% proof stress of 150 MPa or more as measured in a tensile test under a room temperature atmosphere.

The present disclosure discloses an apparatus and a method for forming a large-scale thin-walled ring shell by hot-press bending with internal gas pressure. The method comprises: welding a first head and a second head to the pipe; arranging a first electrode and a second electrode at the two ends of the pipe; charging compressed gas to the heated sealed pipe assembly; placing the sealed pipe assembly between the convex part of the first die and the concave part of the second die, controlling the temperatures of the first and second dies to perform press bending; increasing the gas pressure in the bent sealed pipe assembly, to attach the bent sealed pipe assembly to the die cavity profile; discharging the compressed gas, cutting the first head, second head and extra material to obtain a formed ring shell segment; welding formed ring shell segments to obtain a large-scale thin-walled ring shell.

Provided are a laser processing method and a laser processing device which prevent a laser irradiation unit from colliding with an edge of a plate material when the laser irradiation unit returns to a portion just above the plate material from an outer part of the portion just above the plate material. The laser processing method for cutting a plate material by laser irradiation, the method including: a plate material end portion holding process of holding a position of an end portion of the plate material at a predetermined position when a laser irradiation unit is present outside a portion just above the plate material; and a laser irradiation unit moving process in which the laser irradiation unit moves from an outer part of the portion just above the plate material to the portion just above the plate material.

A method of preparing antimicrobial surface on medical devices: first, producing multi-functional surface with bacterial anti-adhesion and self-cleaning functions through single-stop ultrafast laser fabrication approach for development of micro/nano patterns, then producing bactericidal thin film through depositing metal nanoparticles on those micro/nano patterned surfaces. The combination of bacterial anti-adhesion and bactericidal film can inhibit initial bacterial adhesion and release heavy metal ions to kill the bacteria simultaneously. Meanwhile, the multi-functional surface with self-cleaning function can prevent the killed bacteria from accumulating at the substrate surface, thereby obtaining long-lasting antibacterial effect.

A friction stir joining device includes a tool, a rotary driver, a linear-movement driver, and a control device. The control device is adapted to (A) dispose so that a first member opposes to the tool, and the first member, a second member and a third member are located in this order, (B) control the linear-movement driver and the rotary driver so that a tip-end part of the tool presses a joined part of a to-be-joined object while the tool is rotated, (C) control the linear-movement driver and the rotary driver so that the third member softened extends above an upper surface of the second member, and the tip-end part of the tool reaches a first position, and (D) control the linear-movement driver and the rotary driver so that the tool is drawn out from the joined part while the tool is rotated.

Provided is a joining method that can prevent a plastic flowing material from flowing out from a butt section and that can reduce the thickness and weight of metal members. The joining method is for joining a first metal member and a second metal member by using a rotary tool comprising a stirring pin, and is characterized in that: the stirring pin comprises a flat surface perpendicular to the rotation axis of the rotary tool and comprises a protruding section protruding from the flat face; and in a friction stirring step, the flat surface is brought into contact with the first metal member and the second metal member, and a front end face of the protruding section is inserted deeper than an upper overlapping section to join an upper front butt section and the upper overlapping section.