钼金属剪切-流动复合热态旋压工艺研究

Study on hot multi-spinning processing of shearing and rheological deformation of molybdenum

摘要:

通过分析蓝宝石单晶生长用旋压钼坩埚的服役过程、钼坩埚的不同部位对蓝宝石生长的作用及影响规律,给出了旋压钼坩埚的失效形式和质量控制要素。通过试验研究旋压载荷因素(旋轮成形角α、旋轮半径D<sub>ρ</sub>、旋轮尖角半径ρ、旋轮安装角β、旋轮布局)、壁厚道次减薄率ψ<sub>t</sub>、旋轮进给量f、芯模-旋轮间隙δ、主轴转速n、旋压温度、加热方式、退火温度和时间等工艺参数,分析底部圆弧部分外裂纹、底部圆弧部分内裂纹、侧壁部分外表面过深毛刺、口部开裂、侧壁壁厚不足、周向壁厚不均、底部圆角下塌、口部尺寸误差控制等钼坩埚缺陷的影响因素、形成原因及其解决方法,开发出钼金属剪切-流动复合热态旋压工艺。同时,给出了钼金属旋压过程中显微组织演变规律。

Abstract:

The service performance and effects of the different details of spun molybdenum crucible on sapphire crystal structure and during the preparation of sapphire single crystal were analyzed, based on which the failure forms and elements of quality control of spun molybdenum crucible were proposed. The hot multi-spinning processing of shearing and rheological deformation of molybdenum plate was developed, and its processing parameters, including spinning wheel load factors (roller forming angle α<sub>0</sub>, roller radius D<sub>ρ</sub>, roller radius ρ and angle adjusting angle β), wall thinning rate ψ<sub>t</sub>, roller feed f, core mould - roller clearance δ, spindle speed n, spinning temperature, heating method, annealing temperature and annealing time, were experimentally studied. The quality affecting factors and causes and solutions of molybdenum crucible, including outer and inner cracks in bottom corners, deep burrs in outside surface of side walls, cracks in open ends, collapsed bottom corner, insufficient wall thickness, circumferential uneven thickness and size errors in open ends, were comprehensively discussed. Meanwhile the evolution law of microstructure during the spinning process of molybdenum metal was presented.