Development and performance test of CuCrZr/316 L explosive welding plate for EAST Lower divertor heat sink

•CuCrZr/316 L explosive welding plate can achieve super high vacuum tight.•The mean extension strength of composite samples is 388.3 MPa.•Test showed the explosive welding plate can be applied in tokamake vacuum vessel reliably. As a key material for manufacturing EAST lower divertor heat sink, high-quality CuCrZr/316 L bonding plate is preferred to be manufactured by explosive welding, which is advantageous in zero input heat without deteriorating the material performance of CuCrZr and 316 L. In accordance with various detections and analyses of CuCrZr/316 L after the explosive welding: metallographic phase and electron microscope analysis showed the bonding interface contains no cavity or Cu/Fe metallic mutual dissolution; tensile stress of the bonding interface is higher than that of the CuCrZr material; a hollow heat sink sample (3 mm wall thickness) made of this material can withstand 4.5 MPa water pressure without deformation or leakage, and has been successfully undergone helium leak detection (200℃, 1 MPa, 1 × 10−11 m3/s). Such test results showed the bonding plate by explosive welding met all high quality requirements on fusion engineering that it can be applied to EAST divertor reliably.