控温策略优化对电子束选区熔化成形TC4钛合金力学性能的影响

Influence of Temperature Control Strategy Optimization on the Mechanical Properties of TC4 Titanium Alloy Fabricated by Electron Beam Selective Melting

摘要:

电子束选区熔化是一种真空条件下高温成形的粉床式增材制造技术，高温度场的控温策略对成形性能与制件组织力学性能均具有决定性影响。采用电子束选区熔化成形TC4钛合金试样，开发了以平均束流为判据的综合控温策略，实现了适应填充截面积变化的自主控温策略，并基于过程预热方法，开展了热量分配策略研究，分析其对力学性能的的影响。结果表明：无过程预热且平均束流较低时，TC4钛合金的抗拉强度为979—995 MPa，并且随平均束流增加呈先上升后下降的趋势；加入过程预热并和填充多重耦合后，提高了温度场的精确控制能力，从而提高了电子束3D打印产品的力学性能。

Abstract:

Electron beam selective melting （EBSM） is a powder-bed additive manufacturing technology that involves high-temperature forming under vacuum conditions. The temperature control strategy of the high-temperature field has a decisive influence on the forming performance and mechanical properties of the fabricated components. In this paper， TC4 titanium alloy samples were formed by EBSM， and a comprehensive temperature control strategy based on the average beam current was developed. An autonomous temperature control strategy was implemented to adapt to changes in the filling cross-sectional area. Based on the process preheating method， a heat distribution strategy was developed， and its influence on the mechanical properties was analyzed. The results show that when there is no process preheating and the average beam current is low， the tensile strength is 979—995 MPa， and it tends to increase and then decrease with the increase of the average beam current. With the addition of process preheating and multiple filling coupling， the precise control ability of the temperature field was improved， thereby improving the mechanical properties of the EBSM 3D printed products.