Object array in FormData passing 0 objects to controller

I'm making an ajax call to the controller passing the FormData(), which has an array of objects along with few other properties. In my controller, the list array which I'm passing seems to have 0 elements. Please help!

Script in cshtml view -

    var _getFormDataToJson = function () {                            
            var applyDetail = [];
            $(_tb).find('tbody tr').each(function (i, v) {
                var trans = {
                    effectiveDate: $(this).find('.effectiveDate').val(),
                    amount: $(this).find('.amount').val(),
                    empLeaveHdID: $('#tx-leaveHdID').val(),
                    //attachmentUrl: $(this).find('.leaveAttachment')[0].files[0]
                }

                applyDetail.push(trans);
            });

            var formObj = new FormData();
            formObj.append('remark', $('#tx-remark').val());
            formObj.append('leaveAppType', $('#hdnLeaveAppType').val());
            formObj.append('applyDetail', applyDetail); //this collection has 0 items in controller

            return formObj;
        }

        var _sumbitForm = function () {
            var formData2 = _getFormDataToJson();               
                $.ajax({
                    url: '@Url.Action("ApplyLeave", "Leave")',
                    type: 'POST',
                    processData: false,
                    contentType: false,
                    data: formData2,
                    //data: { data: formData2 },
                    success: function (data) {
                        if (data.success) {
                            _myToastr.success(data.msg[0], true, function () {
                                location.reload();
                            });

                            $(_modal).modal('close');
                        }
                        else {
                            _myToastr.error(data.msg[0]);
                        }
                    },
                    complete: function () {

                    }
                });
            }            

Controller -

 [HttpPost]
    public JsonResult ApplyLeave(Hr_LeaveApplyHd data)
    {
        foreach (var detail in data.applyDetail) //applyDetail count is 0 here
        {
            //to DO:
        }

        return new JsonResult();
    }

EDIT: Hr_LeaveApplyHd model -

public class Hr_LeaveApplyHd
{
    public Hr_LeaveApplyHd()
    {
        applyDetail = new List<ApplyDetail>();
    }

    [Key]
    public int applyID { get; set; }
    public string remark { get; set; }
    public virtual List<ApplyDetail> applyDetail { get; set; }
    public LeaveAppType leaveAppType { get; set; }
}

applyDetail model -

public class ApplyDetail 
{
    [Key]
    public int applyDetialID { get; set; }

    public DateTime effectiveDate { get; set; }
    public decimal amount { get; set; }

    public int empLeaveHdID { get; set; }
}