Sn63Pb37熔融涂覆成形数值模拟及扫描方式对力学性能的影响

Numerical Simulation for Sn63Pb37 Fused Coating Additive Manufacturing and Effect of Scanning Strategy on Mechanical Properties

针对现有增材制造技术对打印材料要求较高、成本较高、成形速率低的问题,提出了金属涂覆成形新工艺。以低熔点合金Sn63Pb37为数值模拟和实验材料,研究了涂覆成形过程的温度场及速度场,分析了数值模拟和实验中两个主要参数(基板移动速度v、涂覆头距基板初始距离H)对涂覆层尺寸的影响,并将同样参数下模拟所得涂覆层尺寸与实验件尺寸进行对比。将涂覆件制作拉伸测试件,分别测试其平行于涂覆方向和垂直于涂覆方向的抗拉强度。研究发现:数值模拟与实验所得涂覆层高度和宽度的最大误差分别为6.45%、6.51%,随基板运动速度的增加,仿真与实验件的高度和宽度均呈下降趋势;当初始距离在1.2mm以下时,随H的增加,仿真与实验件的高度与宽度均增加,且增加速度较快,当H大于1.2mm时,趋于平稳;涂覆成形件平行于涂覆方向和垂直于涂覆方向的抗拉强度均高于原铸件,其中平行于涂覆方向的抗拉强度最大,达到46.63MPa,比铸件高出30.49%;平行于涂覆方向较垂直于涂覆方向的韧窝密且深,从而平行于涂覆方向的抗拉强度要高于垂直于涂覆方向的抗拉强度。

A new process of fused coating additive manufacturing is proposed to solve the problems of high requirements for printed materials, high cost and low manufacturing efficiency in the traditional additive manufacturing. Considering low melting point alloys Sn63Pb37 as the experimental material, the temperature field and flow field of coating are numerically investigated. The effects of two main parameters, substrate velocity and distance from the substrate to coating head, on the width and height of coating parts are also discussed. The obtained size of the coating parts is compared with that of the experimental one. The experimental specimens are prepared for tensile testing to evaluate their tensile strength parallel and perpendicular to the scanning path, respectively. The deviations of the height and the width of the coating parts between numerical simulation and experiment get 6.45% and 6.51% respectively. With the increase in velocity of the substrate, the heights and widths from simulation and experiment decrease. With the increase in initial distance H, the heights and widths increase rapidly, and the increasing rate tends stable as H〉1. 2 mm. The tensile strength of the coating parts parallel and perpendicular to the scanning path gets higher than the tensile strength of the raw materials, especially in the direction parallel to the scan path, it reaches the maximum 46.63 MPa, and 30.49M higher than that of casting. The dimples are denser and deeper in the direction parallel to the scanning path than in perpendicular direction, thus the tensile strength in the direction parallel to the scan path is superior to that in perpendicular direction.