钛合金搅拌摩擦焊接构件显微结构及力学性能预测中的计算方法

The formation of the different welding zones can be simulated based on the numerical investigation on the material flows and the numerical model of grain sizes in friction stir welding (FSW) of titanium alloy. The mechanism for the different welding zones can be then explained and the relation between the welding parameters and the welding zones can be established. The computational model of the precipitation in FSW can be established based on the Johnson-Mehl-Avrami model. The coupled model with consideration of both the grain growth and the precipitations can be built based on the cellular automata model. The mechanical properties of the weld can be then predicted based on the strain hardening model with consideration of the precipitation evolutions. The cellular automata model and the numerical model for prediction of mechanical properties in micro scale can be connected to the thermo-mechanical model of FSW in macro scale. The multi scale computational method can be then developed. The computational methods and the numerical models of FSW can be further improved.

通过对钛合金搅拌摩擦焊接材料行为的研究及所建立的搅拌摩擦焊接晶粒预测模型，界定钛合金搅拌摩擦焊接过程中不同的焊接区域并解释其形成机理，建立焊接参数与焊件区域之间的关联。基于Johnson-Mehl-Avrami模型建立搅拌摩擦焊接沉淀相计算模型，进一步结合元胞自动机法建立考虑再结晶因素的晶粒生长和沉淀相演化耦合模型，结合基于沉淀相变化的应变硬化模型，构建钛合金搅拌摩擦焊接力学性能预测模型。以图形返回算法为基础，建立微观元胞自动机模型和力学性能预测模型与宏观热力耦合模型的关联，系统性研究宏微观参量之间的相互影响关系，发展宏微观一体化的计算方法，进一步建立和完善搅拌摩擦焊接的数值模型和计算方法。

通过建立搅拌摩擦焊接的Monte Carlo模型模拟了再结晶和晶粒长大的过程，将工艺参数与晶粒形貌和尺寸联系起来，发展了两尺度Monte Carlo模型模拟了钛合金在搅拌摩擦焊接过程中的beta-alpha相变。通过不同模型预测了钛合金、铝合金的力学性能，通过晶体塑性模型研究了不同晶粒形貌和尺寸下的搅拌摩擦焊接构件的力学行为。建立了搅拌头磨损的计算模型，将焊接质量和搅拌头磨损程度进行了关联，通过试验验证了磨损搅拌头下用于晶粒预测的Monte Carlo模型。共发表和录用SCI期刊论文23篇，发表国内期刊论文23篇，参加国际学术会议24人次，其中邀请报告5次，参加国内学术会议16人次，其中邀请报告2次。专著2部，授权实用新型专利6项。