Abstract: The present disclosure provides a wire and arc additive manufacturing (WAAM) method for a titanium 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. This WAAM method completely breaks dendritic structures and refines grains in the WAAM process of the titanium alloy, thereby effectively repairing defects such as pores and cracks.

Abstract: 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.

Abstract: A global shutter image sensor with improved pixel failure coverage detects failures caused by the pixel chip of the image sensor. The global shutter image sensor includes a pixel chip including an array of photodiodes and associated logic, and a logic chip, bonded to the pixel chip, including an array of logic blocks for processing the images detected by the photodiodes. A failure detection circuit coupled to a reference voltage node of the image sensor detects a failure in the pixel chip by capturing a first level of pixel bias current and a second level of pixel bias current wherein a difference between the first level and the second level drives an output of the failure detection circuit either as logic high or as logic low.