You can download the machine from either Customersource or Partnersource.
- Customersource:https://mbs.microsoft.com/customersource/northamerica/AX/downloads/service-packs/AX2012DemoToolsMaterials
- Partnersource: https://mbs.microsoft.com/partnersource/northamerica/sales-marketing/demo-tools/virtual-machines/AX2012DemoToolsMaterials