Rheo-casting of Al based wrought and cast alloys via controlled diffusion solidification

CDS是一种新型的流变铸造工艺，可通过控制扩散凝固实现铝基变形合金和铸造合金的净成形铸件。 该项目第一阶段的目标已经实现，并成功开发了CDS所涉及的机制的知识库和对加工参数所需的控制。CDS作为一种工艺也引起了汽车行业的极大兴趣，并且已经启动了开发用于汽车部件的新型合金的具体项目。该项目的拟议第二阶段将致力于开发特定的合金化学和加工这些合金所需的工艺参数。将为CDS工艺开发2xxx、3xxx、4xxx、5xxx、6xxx和7 xxx合金系列的特定铝锻造合金，并将其铸造成净形部件，并对其机械和性能特性进行量化。本研究将采用两种主要工艺：高压/挤压压铸和倾斜浇注金属型铸造。在该项目的第一阶段中被确定为关键的工艺参数是两种前体合金的熔体过热、混合的质量比、第二种合金向第一种合金中的浇注速率、铸造混合合金之前的等待时间、模具预热温度。每个最终所需的合金化学成分对于上述每个工艺参数都具有特定的操作窗口。拟议的研究计划的目标包括设计和开发个别前体合金，并优化上述工艺参数。正在开发的合金具体来自2xxx、3xxx、4xxx、5xxx、6xxx和7 xxx系列的铝锻造合金。具体任务是量化浇注方法和第二合金的浇注速度对所得组织和性能的影响，优化用于CDS的高压/挤压压铸和倾斜浇注金属型铸造工艺的工艺条件，开发指导书以呈现CDS铸造各种合金的程序的具体详细说明，并评估机械性能，例如拉伸、疲劳、所有铸造合金的蠕变和磨损。

CDS is a novel rheo-casting process to facilitate the net shaped castings of Al based wrought and cast alloys by Controlled Diffusion Solidification. The objectives of the first phase of this project were achieved and the knowledge base for the mechanisms involved in CDS and the control required on the processing parameters have been successfully developed. CDS as a process has also attracted significant interest from the automotive sector and specific projects to develop novel alloys for automotive parts have been initiated. The proposed second phase of this project will pursue the development of specific alloy chemistries and the process parameters required to process these alloys. Specific aluminum wrought alloys from the 2xxx, 3xxx, 4xxx, 5xxx, 6xxx and 7xxx alloy series will be developed for the the CDS process and cast into net shaped components and their mechanical and performance properties quantified. Two main processes will be used for this study: high pressure/squeeze die casting and tilt pour permanent mould casting. The process parameters identified as critical in the first phase of this project are melt superheats for the two precursor alloys, mass ratio of mixing, rate of pour of second alloy into the first alloy, wait time prior to casting the mixed alloy, mould pre-heat temperature. Each final desired alloy chemistry has a specific windows of operation for each and every process parameter mentioned above. The objectives of the proposed research program include the design and development of individual precursor alloys and optimize the above mentioned process parameters. The alloys being developed are specifically from 2xxx, 3xxx, 4xxx, 5xxx, 6xxx and 7xxx families of Al wrought alloys. The specific tasks are to quantify the effect of pouring method and rate of second alloy on the resultant microstructure and properties, optimize process conditions for high pressure/Squeeze die casting and tilt pour permanent mould casting processes for CDS, develop a guide book to present the specific detailed instructions on the procedure to cast various alloys by CDS, and evaluate mechanical properties such as Tensile, Fatigue, Creep and Wear for all the alloys being cast.